I am the same and don't know what's wrong with me as have turned into a complete wuss. If it's raining or cold I won't go out. I must be getting old/lazy/both.
I am the same way, I went out today with rain forecast but not raining when I left my house. I was going out as more of a test run to see how my jacket from an old motorcycle rain suit would do while riding a bicycle. When I looked at my time at about mile 3, I was like hmmm...might have a shot at a good time on this route.
I kept the pace up to about the half way point, only slowing down to get out some tissue to wipe my runny nose
(I know TMI, sorry). I got to about the half way point still looking good on the clock and having to unzip the boil in bag jacket. When I hit half way it starts raining, not really hard but steady. The temperature dropped quickly as well. I zipped the jacket all the way up again and kept spinning. I thought the rain would kill my time as there was a slight headwind in the return direction but I kept on aggressively spinning. The headwind went away after a few miles and I made it back home in record time for that route....by over 1 MPH avg speed as well.
Just getting dressed to ride and getting out the door is the hard part sometimes. If it had been raining before I left home, I may not have gone out. Some of my best rides have been when I didn't really "feel" like going out ,but after a couple of climbs in the first two or three miles, I normally feel a lot better than if I had stayed at home with my feet up on my desk or on the couch.