This is a "funny" time of year, when daily wardrobe adjustments are part of the bike-transportation experience. For example, in the morning when the temperature is around 40 degrees, I wear a jacket (and occasionally regret not wearing my thicker gloves, which will come out in another 10 degrees). By afternoon, I'm usually riding in shirt sleeves and shorts, with jacket stowed in fanny-pack. (It works out pretty good, because I carry my sack lunch in the fanny pack, and that space is vacant for the jacket in the afternoon.)
Yesterday I was riding home, at 5:30pm or so. I was wearing my work slacks and had put on my T-shirt. I was very comfortable; in fact I was gloating about how fantastic I felt.
When lo and behold, here comes this gal on her bike in the opposite direction. She was wearing what looked like a down-filled expedition parka, several inches thick. She had on a thick stocking cap and earmuffs (!), heavy knit scarf around her neck, and what looked like a neoprene cover over her face. Thick gloves. Napoleon Dynamite moon boots.
Maybe she's not from around here... maybe she was visiting from Phoenix. Either her thermostat, or mine, is busted.
(I realize that I'm blessed with some awesome physiology - I have a layer of fat that many cyclists have to do without! Poor pathetic beings! And I'm also the first to declare that I seem more tolerant of temperature variations than most people are. I think regular cycling helps in that regard. Danielo has mentioned the same thing. It is a blessing to be comfortable, whether the temperature is 45 or 95 degrees. The Missus prefers the 70-73 degree range, and if it's not there, she takes measures to fix the problem.)