Lots of snow. Lots of cold. Lack of insulation Not using an exhaust fan No roof overhang. All contributed to my leaking ceiling. Some of these are corrected: Snow is cleared. Insulated the .... of that area. Using the exhaust fan during and then 10 minutes after showers/baths. Cannot change the cold. Cannot change the fact that I have a Mansard Roof. Live and learn for my forever house.