Just put in a training session yesterday where it started to rain torrentially just as I started (if only I could synchronise other things in my life with the Man up there...). I really wanted to quit, but considering I had my trainer there and only have 4 weeks to recover from a 2 months Achilles injury for my first marathon, that was a no go.
Result? I felt absolutely elated by the end, having put in a massive session and disregarding the absolutely soaking wet clothes. Basically felt like He Man during the run and loved it.
As my trainer kept on saying, there is no wrong weather, just wrong gear!