Faulty Battery
If you have trouble starting your car (it may not be because of the -20 degree weather) and your car’s clock or radio presets are frequently cleared, you may have a problem with your battery that is causing the engine to stall.
The key is to have a set of jumper cables ready so you can jump start your other car if your battery dies, and get straight to the repair shop (a portable battery booster has the same functionality if your battery dies, but you don’t need a second car).
Unfortunately, there’s nothing you can do about a faulty battery other than buying a new one. Car batteries usually last about 5 years. If your battery is old, consider replacing it before it causes problems.