Zeta taught me something, yesterday:
Did you know that you can look up doppler radar for your area, on line, at a weather site? If you have an internet enabled cell phone or laptop with you, and you are caught in a sudden summer storm, the radar display lets you know how large the bad area of the storm is and you can see whether it is moving away. Or whether you are in for more windblown drenching.
Our local television channel 4 has doppler radar available. I discovered that if you look at the time stamp for the beginning of the radar loop and at the time stamp at the end of the loop, you can almost guestimate how long it will take for that little hole in the clouds to open up over you so you can run to your car. Our radar display is about five minutes behind real time which isn't too bad.
'Course you could always stand out in the rain looking up. But, I don't recommend it. . . .