Its actually the surface temp that makes it difficult. UPP has enough oils in it, its not going to immediately dry up on you, and its not like it needs to be worked in either. Intense heat wouldnt be a good idea, average day 70's-80's, I dont think youll have a problem. I actually encourage using the sun to assist in removing oils after your intial hand removal. I like to let it sit in the sun to warm the surface, which will thin out remaining oils, then wipe away while still in the sun. Works like a champ.