Canister stoves work better at alititude in cold weather. You see pictures of high altitude climbers using them all the time. At lower elevations and cold weather, the gas will not evaporate. My canister stove (Primus Micron) worked at Yosemite at 7K at 15F-20F.

Markill makes a canister pad that heats up the canister. Not sure how it generates the heat. The description says you heat it up first, so kind of a Catch -22; how do you heat it up if your stove isn't working to begin with? It looks like a mini frisbee or coaster. Saw it on a UK camping gear site.

http://walkhigh.co.uk/acatalog/Stoves_and_lanterns.html