For the past two winters, we have had leaks around three of our upstairs windows. I saw somewhere that this could be the result of clogged soffits. I suspect it could also be poor attic venting.
Answer:
It could, and probably is, also be caused by caulking having been overwhelmed on the top and two sides of the window where it meets siding. If it is caused by anything in the attic, your problems go beyond clogged soffits or poor ventilation. You'll have to look at the amount of insulation, continuous vapour barrier in that area and then, check for both upper and lower attic cavity ventilation.
