Cold. Anything past -30 and I'm bundled up fatter n' a michelin man. Right knee gets so bad I can't hardly move it. Wearable rechargeable heat packs are lovely. Too warm though and I get "too" flexible and can actually have a joint just bend the wrong way and WHAM I'm down. Old farts with double joints really are bad off lemmie tell ya. I have so far managed to tell the docs to go stuff it other than some cleanup work but it's only a matter of time.