Totally - for one thing, you're going to be pedaling a lot harder than in warm weather, overcoming resistance in every bearing system in the bike, extra rolling resistance in your tires, extra resistance from the uneven surfaces you ride on... Plus some extra muscle tension as you get used to the ride (mentally) and as your body keeps muscles ready to shiver and generate heat as needed. (Try doing an indoor warm-up with some plyometric stretches, really getting the blood moving, before going out to ride, and see if that makes a difference).

But I am willing to bet a big part of it is dehydration. You won't feel as thirsty riding in cold weather, and you may not be sweating, but your body is burning through a hell of a lot more water keeping your metabolic rate up, and you are losing a huge amount of water in your breath.

That's the hardest thing for me to remember every winter. (This is year 8 riding into winter in Calgary - where it is *very* cold, *very* dry, and very high altitude )