Well, arctic air and blasting furnaces don't do my skin any favours, either.
My skin gets very greasy in hot humid weather, although that doesn't seem to make it more prone to breakouts. The zits seem hormone-related. It does cause some makeup related hilarity, though.
My skin isn't particularly great if it's very dry out -- it can get a bit dry and tight, and I need to wear heavy moisturizer.
My skin looks best when I've had lots of sleep, I've drunk lots of water, I'm not stressed and I'm mid-cycle.
It looks its worst after skiing in dry cold weather or in the middle of final exams, and at "that time of the month".