Apparently the phrase "dog days of summer" originates with the Greeks and Romans, who recognized that the hottest, most miserable part of the summer occurred in late July when the constellation Sirius rises along-side the sun in Late July.
However, the Greeks and Romans didn't live in Salt Lake City in the 21st century when the dog days just seem to go on and on.
Really, late July is climatologically the hottest part of the year here and that was the case this year. The hottest days of the year, in terms of average temperature, were July 17 and July 22 (91.5 and 91.0˚F, respectively). Given the long nights, we won't be touching that this week or weekend, but it's going to be hot.
Below is the GFS forecast valid 0000 UTC 2 September (6 PM MDT Thursday). Monsoon moisture is confined mainly to southern Arizona and New Mexico and ridging predominates to our west. 700-mb temperatures at KSLC are around 16–17˚C. The long-term median for Sep 1 is about 10˚C and the highest ever observed after 23 August is 17.2˚C.
In other words, this airmass is quite warm for so late in the year.
Sadly, that means an extended run, beginning tomorrow, with highs in the upper 90s to near 100. At least the shorter days, low humidity, lower angle sun, and overnight lows near 70 should make it a little more tolerable than the true dog days in late July.