Depends on where you hunt, but my experience is the rut is usually the hottest between the 20-25th of September. This last year, things were just starting to get interesting the last two days of the general archery season. Don't misunderstand--I've seen the elk going crazy the 1rst week of September (this was on a LE unit down south), but in norther Utah, year in year out, it seems to be the third+ week of Septemeber.