You really need to make sure your hoodie is some kind of higher end material for this though. It doesnt need to be water resistant or anything for a hoodie to be a good base layer, but if you go with a hoodie you pick up at wal-mart its going to make you colder in the long run. Example, the Saga riding hoodies are made from full poly so they breath a little better and are not as cold when they get damp with sweat.