Last week I wimped out (twice) because of rain or forecast heavy rain.
Last night was a beautiful night to be riding. A few clouds, but clear, not too chilly. Today? Rain. Small droplets, but lots of them, covering everything on my "dashboard" within a couple blocks, and messing up my glasses. (At least it's sort-of distilled water!) But it was warm enough that it wasn't unpleasant, and I didn't melt.
It'd still be more fun if it was 80 degrees instead of 55.