It snowed today in parts of New Hampshire, and in other parts the Connecticut river is over its banks and the flood warnings are out for local streams . . . which is a good enough reason to think about the use and misuse of weather in fiction.
For example, there’s emotionally appropriate weather: whenever the protagonist is depressed, it rains; whenever the protagonist is happy, the sky is blue and the sun is shining. You can get away with this maybe once per novel, if you’re lucky and if your readers don’t notice what you’re doing. Use a light hand, and don’t milk your effects.
Then you’ve got ironically inappropriate weather: your protagonist is depressed, but it’s a glorious day out; your protagonist is deliriously happy, but the rain is pouring down. Again, use a light hand. If your narrator or viewpoint character feels obliged to point out the irony, you’re probably overdoing it.
There’s also plot-complicating or plot-resolving weather. The rule of thumb here is similar to the rule of thumb for luck or coincidence: weather effects that make things worse for your protagonist will be more readily believed than weather effects which make things easier. (Also, be parsimonious about these things. Readers will buy one instance of bad weather-luck; you’re pushing it if you expect them to buy three or four.) With weather, remember also to keep your weather patterns appropriate for the region and the season, and don’t forget to lay the groundwork in advance. A thunderstorm at the end of the chapter needs a hot afternoon and thunderheads on the horizon at the beginning of it.
Finally, there’s weather that’s gone missing — stories where every day is neither overcast nor blindingly sunny, neither excessively hot nor excessively cold, neither excessively windy nor a dead calm, neither swelteringly humid nor parchingly dry. We’re writers, people; we don’t need to wait for good weather to film our stories; we can give our chosen locale its full range of seasonal effects. And we had better, because if we don’t, our readers will notice that something is missing.