Wear easily removable layers. T shirt and arm warmers instead of a long sleave shirt allows me to start off cool and peel off the warmers as needed. I also weara windproof vest witha mesh back, and use panniers. I noticed a big difference when i ditched the backback for the bags. Dont wear cotton, try dryfit as it allows sweat to easily evaporate. The shirts stink though when they get sweaty. I keep unsented babywipes on my desk to wipe down as needed.