on Jane Friedman site:
Writers are sometimes told not to write about weather. It’s boring, right? An unimportant element that adds nothing useful to a story. Dry details. Who wants to read about a dark and stormy night? No wonder Snoopy never got past typing that first line of his great magnum opus.
But weather affects us every moment of every day and night. We make decisions for how we will spend our day, even our life, based on weather. And weather greatly affects our mood, whether we notice or not.
Since we want our characters to act and react believably, they should also be affected by weather. Sure, at times they aren’t going to notice it. But there are plenty of opportunities to have characters interact with weather in ways that can be purposeful and powerful in your story.