WRW

I can only empathise. I've had this occasionally for years, just on very cold days (like today). I've not found a permanent fix. Best quick fix so far, if at home, a mains heat gun on the area and it was OK in under 2 minutes. I seem to recall warm water poured over the door near the handle does it too. But for sure it'll happen again. I suppose some tiny amount of water in the mechanism freezes and I imagine stripping the door and drying mechanism with hot air then spraying with WD40 might get rid of it properly but have not tried. I hope someone else has an answer.