The rut in Utah and any other state for that matter is really determined by the condition of the cows--which typically occurs in September (for the most part).
What causes the peak to occur depends on the condition of the cows are in. If they are in good condition it could be early September, if poor condition it could be mid to late October.
Last year 2007 similar to 2002, it was hot dry all summer long and the peak in my opinion didn't occur until mid October. This year I would expect things to be at least normal (in my opinion a few days either way of the 20th of September) from what I would gather from the vegetation and precip we have been getting that it ought to peak sometime around the 20th give or take, it might be earlier in Norther Utah and a few days later in Southern Utah but a few days either way.
It was a cool wet spring which made for great groceries my guess baring any real hot prolonged temperatures and
a bit of rain over the next few days, it will be a 'normal' rut this year.
Todd