Frozen Locks

I did a search and none of the threads I found addressed this annoying issue. When its freezing or below out, my door wont close once it has been opened. I have to hold the door shut with my hip and use the key to lock it closed then climb over the passenger seat to get in. Once the car has been fully warmed up inside or the temps outside rise, the door will work as normal. Would this be a lube issue or is it normal for the actuators to stop working when cold. Any help would be greatly appreciated. Thank you