If you look thru the archieves you will find CS owners from Alaska to Maine and all points between in the northern US along with CS owners in Canada. No problem smoking in cold, sub-zero weather. The CS is so well insulated that these conditions have little to no effect on cooking times & temps. They just keep chugging along tru all four seasons.
My coldest cook was 14˚ with a stiff breeze and my cooking time and temp inside the unit did not vary.
Just for grins, you need to check out
Mainely Dave's website, as CS owner from Maine. Scroll down to the "Sub-Zero picnic shoulder."