This strikes me as odd. I live in Wisconsin, which is not particularly rainy, but also not a desert. I'm a cyclist, for recreation and utility. On rainy days, there are certainly fewer people out on the bike paths, but far from zero. Likewise during the winter. I see people walking past my house, and at the parks, when it's wet out.
There are also people who don't like to be outdoors under those conditions, or who think that it's brave of me to ride my bike to work at -20 F, but I remind them that people work outdoors all day in places like Alaska, and survive.
Naturally, thunderstorms get a bit more attention. Those can produce hail and tornadoes, or blow down trees, with little provocation.