Interesting thing about gasoline engines, they become more and less efficient when the temperature drops.

They become more efficient because the air being brought into the engine is denser and cooler which is better, but they become less efficient because rubber parts become stiffer, lubricant becomes harder to move, and overall everything is tougher to deal with.

One result is that if you drive long ranges in -40C, your fuel economy is relatively similar to what it would be in warmer weather. You can blast the heat and your vehicle is toasty warm since it's just moving waste heat around. I've done such drives many times since resources are not where people tend to be.

As you approach -40 you'll probably want to have your block heater plugged in overnight on a gasoline engine, but generally speaking you can get pretty cold and have the motor turn over just fine. I drove a diesel for a while in the far north and going back to a (really crappy) gas engine was surprising for how easy it was to just get up and go in really cold weather.