However, we will take a run at 90 today at the Salt Lake City International Airport, with temperatures climbing a bit further and peaking even higher tomorrow. The NAM forecast valid 6 PM MDT tomorrow shows a warm, southerly flow in advance of an approaching trough with 700-mb temperatures right around 12ºC.
I've long considered a 700-mb temperature of 12ºC to be the lower threshold of summer misery. Below that and afternoon temperatures in the Salt Lake Valley are tolerable. Above it lies misery, that increases exponentially as temperatures increase further.
Climatology shows this fairly well. 700-mb temperatures average around or above 12ºC at the Salt Lake City airport from early July through mid August. You know. The dog days of summer.