One of the enduring mysteries in photography, at least for amateurs, is how to photograph rain. It's just too translucent and ephemeral a substance to show up proudly in pictures without an effort on the part of the camera operator.
In the past I've googled for ways to do better. There are some good suggestions: photograph toward a light of some kind, such as a street light. Increase the shutter speed, use a tripod. And of course rain at night will show up better against a light source than on simply a cloudy day.
So when it rained one night back in July, I headed outside with an umbrella.
It was alright...definitely better than any failed daytime photos. But I figured there had to be a better way. (I didn't have a tripod)
So, kind of like I just randomly came up with exposure compensation to fix the sky, I wondered if a higher ISO would do the trick. In the photos above the camera was set to ISO800 because it was nighttime; I resolved to try ISO1600. And you know what? It worked.
The technique definitely needs to be refined (and coupled with a tripod) but at least this is a good start. And maybe one day I'll be caught in the rain with all my camera equipment and a nice bright streetlight. :)