Long summer back in 1979 in Idaho Falls, just up the road from you in Pocatello.
First we arrived at INEL/S1W on April 15, the CO told our crew “Last night was the first it stayed above freezing since October ... Welcome to summer in Idaho.”)
Summer can be quite warm and dry. I've experienced a high of 103F during the day with an overnight low of 86F. After a few of those experiences, I spent the money to repair the air conditioner. I haven't needed it yet this year. At the current rate, we won't use it at all.