What's It Like Outside, Ollie? IT'S HOT.

OK, I know we should be happy for the return of 80-degree-plus days this week, and indeed, I am happy to see the warmer weather again, but where did this hot/humid night come from, and when is it leaving?
When the temperature is 74 degrees at 11 p.m. and the humidity is a couple of percentage points lower, it's hot, sticky, and not in the hubba-hubba way, just the my-darn-t-shirt-is-sticking-to-my-back while I sit here typing hot.