It’s not going to hit 100 like the Portland State game played in August! Highs for October in Northern Utah rarely exceed 80 degrees. (Although it’s a given that Fall temps in Utah this year have exceeded the mean) There’s also a possibility the weather will be perfect.
Things that may make your experience a little better. Stay hydrated. Bring sun screen. (North End Zone fans and others are susceptible to sunburn) Bring some shades. The worst of the heat/sun should be dying down by halftime.