I never had a problem as long as I wore shorts during the day, so the wind can get in there and keep everything dry. One day I wore long pants and I could feel the sweat building up after half an hour of walking, so I went back to my tent, washed up, and changed into shorts so I wouldn't get a rash. Only powder can save you from a rash, and I hadn't brought any.
You'll want the long pants at night, though, so bring both.
