Do doors ALWAYS stick in the winter when it is cold and dry? This is contrary to what I would have predicted. I think it would be the other way around. The wood of the door itself, with the grain pointing up/down I thought would shrink inwards, and the rough-out framing wouldn't move, because the grain, running side to side, would not be affected as much. But I have done doors before, and they seem to stick not when it would otherwise be expected.
The substance of answer to the above question is not necessary. However, I do need a practical solution to the following problem. I have 4 doors I have hung by myself into 2x4" rought out with mdf jambs. I thought I had given myself enough of a gap for expansion, etc. I am totally surprised, but after using bondo, shellac, primer, and now one of possibly two coats of oil paint I no longer have enough gap. I have to trim the edges of the doors. This I can do with a power sander as they are hanging and I can just swing them over to check for fit. But how much to sand, now that all I have left to think about is temp & humidity. There seems to be enough gap still on some corners, but it has disappeared at others. It is spring here in Toronto, and I can only guess at the peak of the dryness. But since I cannot reason what is going on, I have a hard time knowing what to do because my intuition and experience tell me completely opposite.