(*) You create a bubble of heat around yourself that extends out to a radius of 30 feet. The bubble provides warmth and light as if it were a bright, sunny day within its area of effect. Creatures within the bubble gain resistance to cold damage and are immune to the effects of extreme cold, such as exhaustion from exposure.
When you cast this spell using a spell slot of 5th level or higher, you can choose to increase the spell's radius or duration. If you choose radius, the bubble's radius increases by 10 feet for each level above 4th level. If you choose duration, the spell's duration increases by 1 hour for each level above 4th level.