heat is a major problem for me! this was my observation that I have recently discovered http://www.acne.org/...at-causes-acne/
have a read.
I'm from Australia and was winter last month and now going through spring. Because it's not hot my skin is unbelievably clear right now. only thing I'm dealing with is PIH which is being treated with Dan's AHA which is working fairly rapidly for me.
Humidity breaks me out like crazy but as someone above mentioned, dry heat while I still get the occasional pimple, it's manageable.