40°, I like to ride in shorts and t-shirt, LOL. Actually, 40's is a tough one because I don't know if it will rise up to 50 and don't have a way to carry clothing. 40's in shorts/t-shirt was an exaggeration, but 50 certainly isn't. Once it hits 50, I need to be in shorts and a t-shirt or I'm sweating worse than 90° mid summer.