Why won't my doors latch back shut when it gets really cold?

There are rods that attatch the door handles to the door latch. These sometimes get oxidized and dont allow the latch to return to its rest position. You will need to remove the door panels from the affected doors and spray lubricant at the pivot points. Also the outside door handle pivot points may need to be lubricated. I know you said you lubricated it already but the lubricant wont get to these points inside the door.