I cycle because I want to, but I did cycle into college yesterday despite the rain (it was wetter the previous 3 days and I did get went then as well, just not on a commute) and despite the fact that my OH cycled to work to leave me the car option. He's trying to make a point that I didn't want making... 1 car, 2 people going in opposite directions means one of us has to cycle, so both of us did yesterday! car's still sitting where it was parked on Wednesday night. Maybe that makes both of us mad, not sure but having been in the aboslutely got to cycle category for years and cycled in in all weathers, its not that bad with the right kit. If its heavin it down on route to work then I use full waterproofs. If it is raining on the way home, only the waterproof jacket gets used (unless it is exceptionally cold as well).
Just cycle when you want to. You will actually find in the long run that you will happily cycle in the rain and enjoy it, or you will avoid it. Just don't use the rain as the excuse... storms on the other hand are a really good excuse and this comes from someone who has tried cycling through the tail end of a hurricane - it does not work particularly well!