
Personally, at this time of year if the weather looks iffy I ride bare-armed and carry arm warmers in case the weather turns cold enough to need them. I also carry a sleeveless waterproof; Assos and Bioracer both make them. If it rains, my arms get wet whether or not the armwarmers are also worn, but they keep the body cool so it does not sweat enough to make the inside of the waterproof fill with condensation.