I haven't noticed any connection with weather. When I got the box, it was summer, hot and humid. Now its winter, cool and dry, mostly. But, I've been having the problem since the first one.

My house is climate-controlled 360 days a year and is 72-78 in the summer and 65-69 in the winter and hovers around 50% humidity year-round, though that shouldn't matter if the humidor is keeping up, which it does.