It depends on how you define warm and cold. Yes, you will be at altitude and in a mountainous region, and you are at the edge of
the rain forest too, so you have to be prepared for all kinds of eventualities. We were there in "winter" and "dry", so we had season, so we had light jackets and long pants. Warm and cold are "relative" terms, so it depends a bit on where you are coming from (...