Some worlds and souls are wrought in fire, descended from light, or arisen from shadow. Others spring forth from frigid crucibles of ice, full of life that is willful and resilient enough to withstand the unrelenting cold. Such individuals may find the frigid environment's reflection on them, discovering a layer of rime imprinted onto their soul. Such sorcerers wield ice and snow with natural grace and skill, finding themselves embraced by the cold instead of embittered by it. 

Solstice Carrier

You are no stranger to the frigid sting of a dark winter night. You gain darkvision up to 30 feet, and you do not suffer penalties for being in cold conditions. If you already have darkvision, it extends an additional 30 feet.

Icy Embrace

Starting at 1st level, you can use a bonus action on your turn to allow a layer of hoarfrost to harmlessly coat you after you cast a spell of 1st level or higher, giving you a +3 bonus to your AC until your next turn. You can only use this feature a number of times equal to your Charisma modifier every long rest.

Blizzard's Grasp

At 6th level, you gain resistance to cold damage. In addition, whenever you cast a spell that deals cold damage, the cold energy that dwells within you latches onto other creatures. This cold energy forces creatures you damage to make a Dexterity Saving Throw equal to your Spellcasting DC, and failures have their movement speed reduced by half. At the end of each afflicted creature's turns, they can make the same Saving Throw to end the effects. 

Cold Intellect

At 6th level, you gain the ability to let the cold ice influence your mind.

You can use an action to allow Winter's chill to gently suppress your emotions, allowing you greater clarity of mind. For the next minute, you gain advantage on all Intelligence skill checks, but disadvantage on all Charisma skill checks.

Freezing Rapture

Starting at 14th level, you can spend 5 sorcery points as a reaction to encase yourself in a layer of near-impenetrable magic ice, protecting yourself from attacks. You resist all types of damage while like this, but you cannot move or take other actions except for Saving Throws. This lasts for a minute or until you end it as an action. When the effect ends, the ice bursts into shards around you, forcing all hostile creatures in a ten-foot radius to make a Constitution Saving Throw equal to your Spellcasting DC. Failures take Cold damage equal to your Sorcerer level. 

Boreal Mastery

At 18th level, you gain immunity to cold damage.

You also have utter mastery over the elements of Winter. Whenever you cast a damage-dealing spell, you can spend 2 sorcery points to change the damage type to Cold. All of your magic reflects the icy power within you. You can also spend an additional 8 sorcery points to remove a spell target's resistance or immunity to Cold damage until the end of the turn.