Disclaimer: not trying to make a climate statement here just genuinely curious.
high humidity hinders evaporative cooling, and extremely low humidity is dessication. overheated core, vs dehydration
This is the source: https://www.ncei.noaa.gov/cdo-web/search?datasetid=GHCND
Not all of the stations have temp data so make sure you pick one with what you want.
Hot summer weather is a UK tabloid perennial favorite, but obviously it hits a bit different here in the US when you've got A/C to go home to!