I definitely think the smaller drops look better! I also brought their alpha down a bit more and added little "splash" effects when they hit the ground. (:
I'm going to clean it up a bit more to get better performance out of it and make it only render rain in pre-determined areas instead of across the whole map, but yeah. Rain. (:
Nadrew is right if you don't have a light source, but the moon is a light source as well, reflecting light from the sun. You can still have a shadow at night as long as some kind of light source is hitting you :P
I'm going to clean it up a bit more to get better performance out of it and make it only render rain in pre-determined areas instead of across the whole map, but yeah. Rain. (: