I keep a lot of detailed personal records...
Going back 40 years to the year I graduated high school, the hottest average daily high temp for July here is 90 degrees...and that occurred in 1983. (MU's climatology numbers support my data) I had 19 days that month at or above 90...61% of the month was in the 90s.
Now - here is the big change. In 1983, during July there were only 3 nights at or above 70. One of which the low was 70. I've already surpassed that this month.
Those are actual numbers. Looking carefully at numbers, daytime highs have definitely trended downward over the past 40 years in July. Numbers back it up. At the same time, overnight lows have increased substantially more than high temps have decreased. The end result is that Julys are indeed slightly warmer on aggregate, and we're suffering more because it simply does not cool down at night like it used to.