Apparently door locks are only tested to -20* F. Of course they are.
Today is the sixth day of record lows here in Fairbanks. The temperature has remained -20 or colder (-38 this morning!) since November 15. Which means that our door is extremely difficult to open. A friend of mine recently got locked out of her place. When she came home from grocery shopping, her lock was frozen. Her normal trick of using a lighter to heat the key wasn’t thawing the lock enough for her to unlock the door. She and her 3 month old infant had to wait until a locksmith could come and drill through her door to get her in. Welcome to winter in Alaska, little one.