On strut braced single Cessnas you'll see the snow accumulate first on the upper corner of the windshield, where it takes the shape of the leading edge of the wing.
Thanks PD, I didn't know that. Useful to know, even though I probably won't be flying in snow in the 182 I fly. In my military Chipmunk days, where we routinely climbed and descended through stratus in icing conditions, the tank vent, sticking up above the wing, made a good icing indicator. It was amazing how quickly the ice built up.
Your post reminded me of Kate Bush's album
50 Words for Snow. Worth listening to - I mean how often do you hear Stephen Fry on a pop album?
Concerning flying in rain, during the first time that I flew in a rain shower - virga, so the visibility wasn't an issue - out of caution, I applied carb heat. The immediate rough-running was so intense, that I instinctively closed the control! Only after a few moments, did I realize it was due to the engine swallowing the melting carb ice. I had never had carb icing demonstrated to me!
The 182 I fly has a carburetor temperature gauge - most useful - I wonder why more aircraft don't have one. Even on the hottest summer days, I often encounter temperatures in the yellow arc on the gauge, which call for partial carb heat.