I had a Canadian friend who used to say "the worst part of Canada is there is no South."
But it's America's hat.
Summer can sod off forever as far as I'm concerned. Anything over 30 degrees C is good for absolutely nothing, IMO. It's far easier to get warm than it is to stay cool.
Don't have an intuitive feel for what 30 C is but if I convert quickly it's around 85 or 86, which is already too damn hot for me. (Not bad off the cuff at 4 AM, eh?)
60 and a light breeze and I'm good to go.
I agree with your statement about warming up vs. cooling off. My line of work is dead in my neck of the woods these days, and I'm at a stopgap position. I'm searching nationally, and I'll go where the work is provided it's not 90 and muggy 9 months out of the year.