Downpour

A dark grey cloud appears above a space you can see within range, releasing a volley of magical rain. Each creature that ends its turn inside a 15 foot wide and 15 foot tall cylinder below the cloud is either Poisoned until the end of their next turn, or gains 1d4 Temporary Hit Points until the end of their next turn. You choose.

The space within the 15 foot cylinder is difficult terrain, and bright light becomes dim light. All Fire damage if halved within this cylinder, and all Cold damage deals an additional 1d4 to a creature within the space.

Using a Higher-Level Spell Slot. The Temporary Hit Points and additional Cold damage are increased by 1d4 for each spell slot level above 1.