My car door wont close shut in winter! I think the lock freezes inside.?

I drive a 2000 Hyundai Accent. On cold days, I open my drivers side car door with my key, but then the door doesnt close shut. I then have to put the heat in the car on full blast on floor head and wait. I then hear a crackling sound (like a lock unfreezing from ice or something), and then it closes. It usually takes about 10 to 15 minutes. If I applied WD-40 on the lock, would this solve the problem?