Best Storm Sorcerer Build - Baldur's Gate 3 (BG3)

Storm Sorcerer Build

The build concentrates on making a Sorcerer that primarily casts Lightning spells. We take the Storm Sorcerer subclass which is perfect for this. It also gives a huge mobility boost by allowing you to Fly via bonus action after a spell is cast. The goal is to reach level 5 as soon as possible to unlock Lightning Bolt, hitting multiple enemies in a straight line.

Being a sorcerer is also a good choice for the main character. As you will participate in dialogues, there will be many options to roll Persuasion, Performance, etc. checks. You can easily be the face of the party as you have high Charisma, and cantrips like Friends and Thaumaturgy allowing you to easily pass these checks.

With this build I will go 12 levels into Sorcerer, however, there are some Multiclass choices if you are interested.

Multiclass Option

However, there is one optimization that makes it a one-turn wonder - multiclass to Tempest Cleric. Why? Destructive Wrath​ allows you to maximize lightning/thunder spell damage. So you can deal the maximum possible damage by using the Channel Divinity Charge. This will require more short and long rests, to reset the expended Charges. So if you do not care about that, multiclassing is a good choice for you.

The biggest problem is that your ability proficiencies get messed up due to how multiclassing works. Spells from external sources like Scrolls and items like Markoheshkir use the last class. So if you are using the Chain Lightning spell from the staff, and your last class was Cleric, you will use Wisdom. Being a Sorcerer this is problematic as it decreases your spell effectiveness.

Here are some progression options with pros and cons.

Setup	Pros	Cons
5 Lv Sorcerer -> Respec -> 1 Lv Cleric/5 Lv Sorcerer -> 1 Lv Cleric -> 5 Lv Sorcerer	You enjoy level 3 spells at level 5. After the respec to 1 Lv Cleric (first) and 5 Lv Sorcerer. You also get correct ability modifiers for your spells, attack rolls, and saving throws. This way you can effectively use spells from Scrolls and weapons like Markoheshkir. The build also works as intended.	The biggest downside is that you lose Constitution Saving Throw proficiency. It also requires some respeccing throughout the game.
5 Lv Sorcerer -> 2 Lv Cleric -> 5 Lv Sorcerer	Straightforward progression and you enjoy the full potential of Sorcerer at level 5.	Your proficiencies get messed up, moreover, spells from scrolls and items don't get your attribute proficiency bonuses. If you are happy with the selections you get through leveling, then this is not a problem, but spells from items deteriorate.
1 Lv Cleric -> 5 Lv Sorcerer -> 1 Lv Cleric -> 5 Lv Sorcerer	You start with Cleric, which gives very good survivability from armor and shield proficiencies. You also get correct ability proficiency bonuses.	You lose Constitution Saving Throw proficiency that would help with spell concentration

Short overview

This is a short overview and progression of the build. Use it to get a glance if you want to pick the best options without going deep into the explanations. A more detailed description with texts, suggestions, and improvements can be found in the next sections.

Storm Sorcerer Leveling Overview

Level	Category	Choice
1	Abilities	Str 8, Dex 16 (15+1), Con 14, Int 8, Wis 10, Cha 17 (15+2)
	Class	Sorcerer 1
	Cantrips	Friends, Minor Illusion, Fire bolt, Ray of Frost
	Spells	Magic Missile, Mage Armour
	Subclass	Storm Sorcery
	Skills	Athletics, Acrobatics, Intimidation, Persuasion, Performance
2	Class	Sorcerer 2
	Spells	Thunderwave
	Class Passives	Metamagic: Twinned Spell, Metamagic: Distant Spell
3	Class	Sorcerer 3
	Spells	Shatter
	Class Passives	Metamagic: Quickened Spell
4	Class	Sorcerer 4
	Cantrips	Shocking Grasp
	Spells	Shield
	Feat	Ability Improvement - Charisma +2
5	Class	Sorcerer 5
	Spells	Lightning Bolt
	Replace Spell	Mage Armour -> Haste
6	Class	Cleric 1
	Cantrips	Thaumaturgy, Produce Flame, Guidance
	Subclass	Tempest Domain
7	Class	Cleric 2
8	Class	Sorcerer 6
	Spells	Counterspell
9	Class	Sorcerer 7
10	Class	Sorcerer 8
	Spells	Banishment
	Feat	Spell Sniper
11	Class	Sorcerer 9
	Spell	Telekinesis
12	Class	Sorcerer 10
	Cantrips	Blade Ward
	Spells	Hold Monster
	Class Passives	Metamagic: Heightened Spell

Starting the Game

We start with the early game. I would go into what are the best Races, Abilities, and Skills for Storm Sorcerer. Some of these choices are impactful as you cannot respec them.

Races

Picking a race provides various benefits - abilities, dialogue options, looks, etc. Overall you would want to get Shield Proficiency or some bonuses to the damage you would do with spells.

Race	Features	Description
Sttrongheart Halfling	Halfling Luck Brave Strongheart Resilience​​	Due to their Halfling Luck, the race is very potent in sustaining concentration on spells, attack rolls, and ability checks. This is not game-changing but still gives a little edge compared to other options.
High Half-Elf	Civil Militia​ Darkvision​ Fey Ancestry​	I think this is the "optimal" choice. High Half-Elfs get a cantrip, Darkvision, and also shield proficiency. More or less everything that you need for a good Sorcerer
Human	Civil Militia​ Human Versatility​	This is one of the rare occasions where I would recommend going with a human. You can get Shield proficiency that will be valuable throughout the game for various bonuses and increased Armour class.

Class

As this is Storm Sorcerer build the first choice is obvious and it gives you all you need for the build - access to mobility, sorcery points, constitution saving throws, etc.

However, if you would like a little more survivability, you could take 1st level as a Cleric and multiclass into Sorcerer. This way you would get heavy armor proficiency, giving a decent amount of protection and shield proficiency. Then at level 5, you could respec back to full Sorcerer. For the build simplicity, we will start with Storm Sorcerer.

Overview
Sorcerer
Features
Spell Slots	These can be used to cast spells and are restored each long rest.

Cantrips

The sorcerer can choose 4 cantrips. This is a lot, allowing us to make some good choices. There are some other choices but I leave those for later levels.

Cantrips	Description
Friends	If you are the main character and do most of the dialogues, this is also a good choice as it gives an advantage during rolls.
Fire Bolt	Use this cantrip to deal moderate damage or light up barrels with oil. Perfect if you want to save spell slots
Ray of Frost	Opposite to Fire Bolt, you can deal ice damage if enemies are resistant to fire damage.
Minor Illusion	Lure enemies together from stealth with the cantrip. Then use Shatter, Thudnerwave, or any other area of effect spell, to deal huge damage.

Spells

Sorcerers cannot prepare spells. This means that what they choose during the level-up screen - is what they can use. This can easily cause decision paralysis especially if you are new to the game. Here are my recommendations for what to pick early:

Spells	Description
Magic Missile	I recommend this spell. It can hit multiple enemies and does not miss. You can easily finish off a straggler with a few HP and damage the second foe.
Mage Armour	Until we reach level 6 and get heavy armor proficiency, this spell will give us 13 Armour Class. Pair this with a dexterity bonus and we have 16 Armour Class at the start of the game. The same as a heavy armor user
Chromatic Orb	Another option that is useful due to the multiple elements it can select for damage. So you can choose the one that the enemy is vulnerable to.

Subclass

Overview
Storm Sorcery
Features
Tempestuous Magic​	After you cast a Level 1 spell or higher you can Fly as a bonus action until the end of your turn without receiving Opportunity Attacks.

Abilities

Now let's take a look at the abilities of the Storm Sorcerer build. Correct allocation will allow us to maximize the early gameplay and get good modifier bonuses.

Ability	Value	Description
Strength	8	We do not need strength as we will not be in close range often.
Dexterity	16 (15+1)	High dexterity will give a good bonus to initiative. Moreover, it will give a bonus Armour Class based on the ability modifier. Later on, if you pick Alert, this could be lowered to increase other stats.
Constitution	14	The constitution will give us bonus HP and increase the success of Constitution Saving Throws
Intelligence	8	Not an important stat for the build.
Wisdom	10	We get 10, to not get any negative modifier for Wisdom Saving Throws, as there are many of them.
Charisma	17 (15+2)	The main ability of Sorcerer build. It determines our spell success, and spell difficulty. Moreover, it is used for many dialogue checks, ensuring that you can trick or persuade NPCs. This assumes, that you will be using Auntie Ethel's Hair for +1 Charisma.

Skills and Expertise

Overall, the skills should be impacted by your roleplaying and background decisions. However, you would still want those that will give you the best benefits. My recommendations are to pick those at which you have a high ability modifier:

• Acrobatics
• Persuasion
• Deception
• Performance
• Intimidation

Detailed Leveling Progression

Here is the detailed progression for the build to get you started. You can use it as a guideline because early games can be daunting and overwhelming. Later on, once you get the feel for the class you can start picking your options

Level 2

Instantly at level 2, we get some sweet stuff. First, you get an additional level 1 spell slot. Second, 2 sorcery points are added, they can be used for creating spell slots, additional spellcasting, etc. Last, we unlock special metamagic mechanic.

Actions	Description
Create Sorcery Points	Spend Spell Slots to gain Sorcery Points. Once you get some more metamagic options, you could sacrifice spell slots, to cast two spells in one turn or increase your range
Create Spell Slot	Spend Sorcery Points to unlock a Spell Slot. You could create a higher tier spell slot, to increase the damage over what you can at the current level

Spells

Spells	Description
Thunderwave	Do you see an enemy close to the ledge? Or they are close to you? Use Thunderwave to knock them back and deal thunder damage. It can instantly kill foes that are thrown from the ledge.
Chromatic Orb	If you did not take it previously, now it is also a good choice.

Class Passives

Sorcerers get access to unique actions - metamagic. They allow to consumption of sorcery points to enhance spellcasting. New metamagic options will be unlocked as we level up as you have more and more Sorcery Points. Choose two:

Passives	Description
Metamagic: Twinned Spell​	Spells that only target 1 creature can target an additional creature. I would say this one is mandatory.
Metamagic: Distant Spell​	Increase the range of spells by 50%. You can easily now avoid the penalty for the lack of range if this situation happens when spellcasting
Metamagic: Extended Spell​	Increases the duration of your spells. Excellent choice for crowd control casting.

Level 3

We unlock the level 2 spell slots and spells. We also gain another option for metamagic, this time much better

Spells and Replace Spell

Level 2 spells are okay, nothing that is groundbreaking. Here are a few recommendations of what you can take. You also can replace spells, but I do not recommend doing that yet at this stage.

Spells	Description
Cloud of Daggers	This can be used to target multiple enemies and is very good in passages or choke points. The spell deals damage when it's cast and when the enemy's turn begins. This means you do 2x damage by default.
Blindness	Amazing spell that does not take up a concentration slot and still provides a decent amount of crowd control against foes.

Class Passives

We are getting another metamagic selection. The good thing is that two new options are introduced. Here is my recommendation:

Passives	Description
Metamagic: Quickened Spell​	By consuming 3 Sorcery points a spell can be cast using bonus action instead of action points. You can cast two damage spells one after another. Or later, you could use Haste and then two spells at the same turn. This unlocks tactical possibilities.

Level 4

We get our first Feat selection that will greatly improve both offense and defense. The Sorcerer also unlocks another level 2 spell slot and can select an additional spell.

Cantrips

We can choose another cantrip. Here is my recommendation:

Cantrips	Description
Mage Hand	Amazing cantrip that summons a spectral hand. It can throw items, shove enemies, and be a distraction. It is also invisible.
Light	This will be useful in Act 2 or if you don't have Darkvision. But take it if you do not see the use for Mage Hand.

Spells

Spells	Description
Shield	I cannot stress enough how powerful this spell is. You can use the level 1 spell slot, to increase your armour class by 5. The result is that you can avoid most of the attacks during the turn.

Feat

For the first Feat, there is nothing much to recommend. You only want to improve your ability score for a higher spell success chance and more damage

Feat	Description
Ability Improvement	Allocate 2 ability points to Charisma. This will increase the modifier by 1 resulting in higher spell success.

Level 5

And we finally reach level 3 spells. Moreover, we get 2 level 3 spell slots for upcasting.

Spells

There are a lot of good spells at this tier, so it's hard to choose what to pick. But as we are a Storm Sorcerer, there is only one true contender:

Spells	Description
Lightning Bolt	A lightning spell that hits all enemies in a direct line. Try to get the best position possible to hit as many foes as you can. Moreover, try to wet enemies with party members for double damage.

Replace Spell

We also need to do some spell replacement. I would suggest removing Thunderwave as you will have Lightning Bolt for Area of Effect damage. Moreover, the next level will bring back Thunderwave.

Spells	Description
Haste	A very powerful spell that gives an additional action point. In a sense, you can cast two spells. Add Metamagic: Quickened Spell, and you can cast 3 spells per turn! It can also be activated on two targets with Metamagic: Twinned Spell​

Level 6

This level is a big step for Storm Sorcerer. You get a swath of new spells, actions and reactions:

Features	Description
Heart of the Storm​	When you cast a Spell of level 1 or higher that deals Lightning or Thunder damage, you cause a small, local storm. All enemies within 6m take additional Lightning or Thunder damage equal to half your Sorcerer level.
Heart of the Storm: Resistance​	You are resistant to Lightning and Thunder damage.

And you gain multiple spells related to your subclass for free:

Spells	Description
Call Lightning	A perfect skill to hit multiple enemies that are close to each other. Also, it can be reused next turns without expending spell slots if your concentration is not broken. However, it will break other spell concentration
Sleet Storm	Amazing crowd control spell that disrupts spellcaster concentration and creates Ice surfaces. After one turn this changes into water. It can be electrified or wet enemies can be hit for double damage.
Gust of Wind	Creates a wide cone of wind that pushes enemies 5 meters and throws them off balance. I use Thunderwave which also deals damage.
Create or Destroy Water	You can use this spell to make your foes wet. It is a perfect choice to be used with Metamagic: Quickened Spell. After that follow up with Lightning Bolt or Call Lightning for double damage.
Thunderwave	It allows you to knock back targets and deal thunder damage.

Spells

We are still able to choose between level 3 spells.

Spells	Description
Counterspell	Another powerful spell that can counter almost any spell that foe casts. Even if you don't use it often, it is good to have it as it will notify you of what enemies are casting and let you decide the next steps

Replace Spell

Remove Cloud of Daggers, and choose from some very good crowd control options:

Spells	Description
Fear	I think the most powerful option. It makes enemies drop their weapons, and they cannot do anything besides run. This has a wide area of effect and ignores allies. Just remember to pick up the foe's weapons!
Slow	You can target up to 6 foes to slow them down. If most of them succeed the combat will become drastically easier and you can overwhelm almost anyone
Hypnotic Pattern	Very deadly against low Wisdom enemies. The spell has a huge area of effect. The only downside would be that it only works for two turns, but this should be enough to take out a few foes.

Level 7

We reach level 4 spells. There are a few powerful options that will synergize well with our Storm Sorcerer build

Spells and Replace Spell

Spell	Description
Ice Storm	Drops Icicles from the sky that deal both ice and physical damage. Creates an Ice surface, which can make enemies fall. This can immobilize large groups of foes as they continue to slip.
Dominate Beast	Take control of enemy beasts to fight on your side. Targeting someone with low Wisdom will allow you to break enemy ranks as they scramble and start fighting each other.

Level 8

The level-up gives the first level 5 spell slot. You can cast very powerful spells by upcasting current ones. moreover, a new Feat is unlocked

Spells and Replace Spell

Spell	Description
Banishment	Remove the target from the battlefield. This can be perfect for making the encounter easier and even disabling enemy buffs temporarily - like auras. The most important thing is that it does Charisma Saving Throw which is very rare and good to have

For replacement, it's your choice, you can pick something you want to try or discard a spell you do not use.

Feat

Feat	Description
Alert​	My recommendation would be this feature. It will make you go first, allowing you to heavily damage enemies or take control of the battlefield before they can do anything
Dual Wielder​	If you do not have shield proficiency, I recommend picking this up. It will allow you to utilize the offhand effectively and equip a second quarterstaff or other item to improve spells. Otherwise, you could delay it for later.

Level 9

And we get to Level 5 spells. All of them are very powerful, but you will be able to cast them one or two times. Another downside is that most of them use a Concentration slot, which is already contending for multiple spells in your arsenal.

Spells and Replace Spell

There are many good choices here but I do not think any of them is "the best". I list a few alternatives that you are free to choose, based on your playstyle. You will continue using Lightning Bolt and Call Lightning for the highest possible damage.

Spell	Description
Cone of Cold	A decent option that targets multiple foes in a cone. The downside is that it does not create any ice or water surface, so besides damage, there are no pros in using it.
Telekinesis	I love this spell. First thing it allows you to play with enemies and throw them around the battlefield. Second, it can be recast without using a spell slot, which is another huge benefit.

Level 10

The sorcerer class gives the last sorcery point, a new cantrip option, a spell, and one metamagic selection.

Cantrips

You are free to take any cantrip that you find useful. More or less the build has been finished, so this is just a good addition:

Cantrips	Description
Mage Hand	Quality of Life spell, that you can use to summon a hand. It can solve some puzzles, pick and throw objects. It can also shove enemies from ledges.
Blade Ward	Reduce incoming piercing, slashing, and bludgeoning damage by half. If you are fighting against enemies that use physical attacks this in theory doubles your HP.

Spells and Replace Spell

We continue with level 5 spells. Generally, pick anything you want to add to the Sorcerer's arsenal. For spell replacement, again, remove what you don't use or want to try. Otherwise skip it.

Spell	Description
Hold Monster	Similar to Hold Person, it allows putting monsters in place. Add a nearby melee attacker or go close with your spell for guaranteed critical hits.
Dominate Person	You can make a person fight for you. Similar to Dominate Beast, this can make encounters much more difficult for enemies as their ranks could fall apart from one strong fighter joining your side.

Class Passives

Passives	Description
Metamagic: Heightened Spell​	Targets of spells that require Saving Throws have a Disadvantage on their first Saving Throw. It will give a higher success of spell success. But overall, at this point in the game, it will not matter much.

Level 11

This is a big stepping stone and unlocks level 6 spells. Moreover, we get the last feature of Storm Sorcerer.

Features	Description
Storm's Fury​	Gives protection against melee-range enemies that dare to attack you. Good use of your reaction.

Spells and Replace Spell

Spell	Description
Chain Lightning	The obvious and most powerful choice for this build. Can also be twin cast using Metamagic: Twinned Spell.

I would also recommend replacing one of not used spells and getting:

Spell	Description
Disintegrate	A deadly single-target spell. You can also use it together with Metamagic: Twinned Spell​ for double damage.
Globe of Invulnerability	Almost a game-breaking spell, makes you invulnerable for 3 turns. This can make fights trivial and can be especially useful if you want to make sure ally NPCs survive fights.

Level 12

We reach the last level of the build, giving the finishing touches.

Spells and Replace Spell

More or less the build has all the mandatory spells, I recommend taking one of those that I mentioned before, or you could get some quirky ones:

Spell	Description
Arcane Gate	Allows to move multiple people through the portal
Greater Invisibility	Very potent when used on your Rogue. Allows you to easily delete enemies while being invisible if you pass Stealth Checks.
Eyebite	You can try this as an option with the build.

Feat

We now get the third Feat of the build

Feat	Description
Alert​	Take this if you have not taken it before. It will make you go first, allowing you to heavily damage enemies or take control of the battlefield before they can do anything
Dual Wielder​	Take this if you have not taken it before. It will allow you to utilize the offhand effectively and equip a second quarterstaff or other item to improve spells. Otherwise, you could delay it for later.
War Caster: Concentration​	Another option if you want to have the highest probability that your spell concentration is not broken.

Illithid Powers

This is a special mechanic in Baldur's Gate 3, that allows you to consume tadpoles and unlock special Illithid Powers. These range from somewhat useful, to extremely deadly. I would like to leave a few recommendations:

Base Illithid Powers

Order	Illithid Power	Description
1	Favourable Beginnings	Very useful power to take as it does not have any costs, and provides only benefits on the first hits.
2	Luck of the Far Realms	Guarantees a critical hit, a very powerful action to have.
3	Concentrated Blast	Taking only for progression, to unlock the next power.
4	Cull the Weak	Passive feature that does not cost anything and automatically deals bonus psychic damage around the target, once it is close to death.
5	Shield of Thralls	Taking for progression, to unlock the next power, but it also provides a good bonus as temporary health.

Elite Illithid Powers

These become unlocked later in the game as you progress. They are extremely powerful additions to the build.

Order	Illithid Power	Description
1	Freecast	Removes any cost of spell slots or charges, allowing you to cast some very powerful spells in case you cannot do that, or want to save Smite slots.

General Tips

Now I would like to cover some general tips on how to play Storm Sorcerer Build.

Twinned Spell and Haste

Even if you did not plan this, Sorcerer can be extremely powerful support. At level 5 you gain access to level 3 spell slots and Haste. This spell gives 2 action points per turn, meaning you could double your damage output.

To do this you need to activate Metamagic: Twinned Spell and then cast Haste. You can now target two targets. I recommend doing this on yourself and another group member. This way two members in your party have double amount of actions. This will make your combat encounters much easier.

Use the Create Water spell

So if we want to hit enemies for the largest amount of possible damage, we need to make them wet. Wet enemies even if they have resistance to Lightning, get bonus damage. Due to this, you should always try to create wet surfaces in most encounters. Now how you can do that?

In the early game, Clerics and Druids gain this spell, so having them cast it is one option. Another option is to throw water bottles. And last, you could get Rain Dancer staff from Arron merchant druid in the Druid Grove

The good thing is that at level 6 Storm Sorcerer you will also gain create water by default. However, you generally want someone else to cast it, to save action or bonus action points (if using metamagic). You also have Sleet Storm, which can be used to create an Ice surface, which melts the next turn into water.

Use metamagic to empower your first turn

You can use the Metamagic mechanic to create some powerful spell combos. My favorite would be Quickened Spell. It allows casting a spell via bonus action. Here are some good combos:

• Haste and then cast two spells on the first turn and three on the second.
• Hold Person or Monster, and then cast spells for guaranteed critical hits.

Moreover, you can use Metamagic: Heightened Spell to create a disadvantage on Saving Throws on enemies. Meaning your spells have a much higher chance of success

Equipment Recommendations

Now I would like to go through some gear recommendations to maximize the Storm Sorcerer build effectiveness. Items are especially important as they take the build to the next level thanks to their unique effects.

Act 1

The early game can be hard, as you do not know where to find items. Picking the correct spells should cover most of the needs. So, as you progress feel free to equip the needed items.

Slot	Item	Description
Melee	Melf's First Staff	Gives +1 to spell attack rolls or DC. An alternative to The Spellsparkler in case it is used by someone else.
	The Spellsparkler	Each hit generates Lightning Charges that later detonate for bonus lightning damage. This staff should also support you in Act 2.
Ranged	Bow of Awareness	Very useful before you get Alert​ feat. The higher initiative will allow you to go earlier.
	Hand Crossbow +1	Equipping two of these will allow you to attack with off-hand. This is important as you may not have used for bonus action if your Sorcery points have been expended, so this will allow some bonus damage.
Shield	Adamantine Shield	It provides a substantial defensive boost by reducing critical hit damage.
Head	The Shadespell Circlet	Increases Spell Save Difficulty Counter, while obscured. Very easy to activate, use Shift, to see the sun icon, it should be half or full empty.
	The Lifebringer	The best defensive option in Act 1. Works well with The Spellsparkler. Without it, the item loses its purpose.
Cloak	Any	Anything will work as act 1 does not have any good options.
Armor	The Protecty Sparkswall	Works well with The Spellsparkler for additional bonuses to Armour Class and Saving Throws with Lightning Charges. The best choice in Act 1.
Gloves	Gloves of Belligerent Skies	Applies Reverbation when dealing thunder or lightning damage. With 5 stacks, this will deal a bonus 1d4 damage and can make enemies Prone.
	Bracers of Defence	Gives whooping +2 Armour Class. This is the perfect option especially if you do not have shield proficiency.
	Gloves of Missile Snaring	Defensive gloves that allow to negate enemy ranged attack.
Boots	Vital Conduit Boots	Because you will be casting spells with Concentration often these Boots will give an additional survivability boost.
	Disintegrating Night Walkers	Avoids slipping on various terrains and most importantly unlocks Misty Step each short rest.
	Boots of Striding	Gives additional protection against being Prone.
Amulet	Pearl of Power Amulet	A good amulet that allows restoring level 3 or lower spell slots.
Rings	Ring of Protection	Gives defensive bonuses to Armour Class and Saving Throws.
	Fetish of Callarduran Smoothhands	Allows Casting invisibility for free once per long rest.
	Ring of Absolute Force	Bonus thunder damage to thunder spells.

Act 2 - mid-game

This is the mid-game, where most of the areas will be covered by dark. Radiant equipment will shine here and having Darkvision​ is recommended. We also can get some great items, albeit some will stay the same from Act 1.

Slot	Item	Description
Melee	Melf's First Staff	These items are still relevant in Act 2 and provide very good bonuses.
	The Spellsparkler
Ranged	Darkfire Shortbow	This bow allows casting Haste without using a spell slot. However, if you do not care about that, continue using the items from Act 1.
Shield	Ketheric's Shield	The only shield that improves the Spell Difficulty class and attack rolls.
	Sentinel Shield	A good option before you get the next Shield. The bonus initiative will ensure that you go earlier if you do not have an Alert​ perk.
Head	Fistbreaker Helm	The best choice in Act 2 for any caster. Gives bonus initiative and Spell Save Difficulty Counter.
	Hat of Storm Scion's Power	An option in case Fistbreaker Helm is taken. You will have to activate Heart of the Storm​ with Thunder damage so that the Arcane Acuity effect would proc.
Cloak	Cloak of Protection	Improves survivability and Saving Throw success.
Armor	The Protecty Sparkswall	Works well with The Spellsparkler for additional bonuses to Armour Class and Saving Throws with Lightning Charges. The best choice in Act 1.
	Robe of Exquisite Focus	A decent choice, but only take it if The Protecty Sparkswall is equipped by someone else.
Gloves	Gloves of Belligerent Skies	You can continue using the same items from Act 1.
	Bracers of Defence
Boots	Evasive Shoes	Gives armor class an increase. Best choice if you are not using Shield
Amulet	Spellcrux Amulet	An amazing amulet that proves valuable in the late game for restoring level 5 and 6 spell slots.
	Amulet of the Harpers	Gives free Shield use per Long Rest. This ensures bonus survivability for Storm Sorcerer.
Rings	Callous Glow Ring	Gives defensive bonuses to Armour Class and Saving Throws.
	Coruscation Ring	It is fairly easy to cast any light spell on yourself or have an ally do that. The Radiating Orb effect will debuff enemies, making it harder for them to hit targets.
	Eversight Ring	Allows Casting invisibility for free once per long rest.
	Ring of Mental Inhibition	Bonus thunder damage to thunder spells.
	Ring of Twilight	Because it is easy to be obscured this allows to gain bonus armour class. Very useful in Act 2.

Act 3 - Final Build setup

This is the last act of the game, where you will get access to the most powerful items. To get them as early as possible you will need some planning, but overall, it should not be a problem.

Slot	Item	Description
Melee	Markoheshkir	The most powerful stave in the game. You can imbue it with different elements - fire, for bonus fire damage, lightning - for higher lightning charge generation. So if going all in on Eldritch Blast, set Bolts of Doom.
	Staff of Spell Power	Gives a bonus to Spell Attack Rolls and Spell Save DC. Also allows casting a spell without using a spell slot per long rest. You can also get Dual Wielder feat and use this together with Markoheshkir.
	Rhapsody	The unique effect that gives +1 damage for each Scarlet Remittance stack. This requires you to kill enemies (previously you could destroy barrels), but this should be easy in late game where normal grunts will be dead from your lightning spells in a few hits.
	Caitiff Staff	The stave is more targeted towards warlocks, but can still be used for bonus Spell Save DC.
Ranged	Darkfire Shortbow	This bow allows casting Haste without using a spell slot. However, if you do not care about that, continue using the items from Act 1.
Shield	Ketheric's Shield	This is still the top contender for the build
	Shield of Shielding	Allows casting Shield as a reaction, giving a bonus layer of protection.
Head	Hood of the Weave	Provides +2 to Spell Save DC for increased spell success.
	Birthright	The best choice in Act 2 for any caster. Gives bonus initiative and Spell Save Difficulty Counter.
	Hat of the Sharp Caster	Improves damage output by rerolling low damage rolls.
Cloak	Cloak of The Weave	This is the best cloak for this build as it gives a direct boost to attack rolls. The result is more successful spells.
	Cloak of Displacement	Improves the chances of attacks missing the wearer until getting hit for that turn.
Armor	Armour of Landfall	Gives advantages to Constitution Saving Throws, increases Spell Save DC, and an additional spell. Moreover, it has a decent Armour Class due to being light armor.
	Robe of the Weave	A very good overall robe that improves spell effectiveness and success rate. A good addition is also
Gloves	Helldusk Gloves	Improves Spell Save DC, for a higher spell success chance.
	Gauntlet of the Tyrant	Improves Spell Save DC, for a higher spell success chance. Also gives a Command spell that can be used each Long Rest.
Boots	Bonespike Boots	Optimal choice if you are wearing a robe and go all in on the dual wielding, this way you get bonus armor class.
	Helldusk Boots	These boots have a wide array of uses - allowing succeeding Saving Throws while using Reaction, a teleportation spell, and ignoring difficult terrain.
Amulet	Amulet of The Devout	I would say this is the best amulet for a spellcaster. It gives whooping +2 Spell Save DC. But it could be used on Cleric, which would utilize it better. However, if you multiclass cleric, then this amulet is mandatory in my opinion, to ensure you can maximize 2 Lightning spell damage per short rest.
	Spell Savant Amulet	You can use the additional spell slot to create sorcery points.
	Magic Amulet	A good defensive option to use Reaction for Saving Throw advantage.
Rings	Ring of Feywild Sparks	The ring gives bonus Spell Save DC, making it easier to land spells. However, this effect is not listed in the description.
	Callous Glow Ring	Deals bonus 2 damage against illuminated enemies. Although it is not much, this also works with spells. Just be sure to cast Light on yourself.

Conclusion

Thank you for reading the Storm Sorcerer build for Baldur's Gate 3. We covered this powerful subclass progression, spell selection, gear recommendations, and ability picks. Moreover, I offered some Cleric subclass options if you are interested in dealing the maximum amount of damage possible.

Cheers!