Why won't my car lock in the cold??

it might just be too cold for your actuators. if you are feeling ambitious you could take your door panels off and lubricate everything with silicone lube.. you could try just doing it in the locks outside, the latches in the door and the lock buttons inside. has helped me before.

I've had a similar problem where the locks won't unlock at the driver door, but it usually goes away and haven't seen the problem in a couple years.