I love weather. Both in real life and literature. It is amazing, delightful, annoying, destructive, healing, and sometimes downright terrifying. But in literature it can be even more.
It always baffles me when writers never mention the weather, or when it’s constantly sunny yet the characters are walking through a jungle of green. Unless there’s a magic system saying otherwise, plants need rain to survive.
Throw some rain on your characters and see what they do. Do they like getting wet? Or are they part housecat and take off like a shot the moment the first raindrop hits? Does your character prefer umbrellas, rain jackets, or giant rain ponchos? How do they feel about sleet? Tornadoes?
Weather can be atmospheric. It can mirror character emotions or evoke them. It can be an obstacle they have to overcome - walking through a snow or sleet storm is no easy task and can be deadly if the storm is bad enough. At the very least the weather can set tone and help establish the world around the character. The weather could even be one of the characters.
There are so many possibilities.
Personally, I love weather in stories. No matter if the character feels attached to it or simply has to find a way to deal with it, weather helps to make the story real; to ground it in something the reader knows and understands. It’s a missed opportunity if you let the weather slide by, in my opinion.