Good question.
I'll ride just about any day. I know how to deal with weather and I'm happy to share what I've learned over the years.
In ten years of bike commuting I never drove. I took the bus once because of thunderstorms but got just as wet as if I rode the bike. I walked twice because of white-out blizzards, due to visibility concerns.
I am a bit paranoid about lightning. A few times I've left home early because of threatening storms. A couple times I waited at work before heading home.
Online weather maps are your friends. You can see in real time when there are breaks in the storm front, as well as judge the timing of an approaching storm.