Same here in northern Minnesota. Temps in the 90F's, humidity about the same. There is an 80% chance of much needed rain tomorrow. Then back to high temps in the forecast.
Like you, I go outside to work for about 30 minutes, then have to come inside to cool off and change tee-shirts. Currently have 4 tee shirts in rotation for working outside. At the end of the day, they get thrown into the dirty wash.

Loved your pics. I planted some Buttercup Squash into an old tire and put it out in the middle of my backyard. Filled it 1:1 with top soil and chicken run compost. Those plants are exploding compared to my other plantings.

Question - is there any concern about growing food in those old tires? Do chemicals from the old tire leech into the soil and then get taken up by the plants? Just wondering, not very concerned....