Grizz, I can't answer the question you ask but I will give you my experience.
I live in the desert southwest, do not have air conditioning and at the moment (19:18) it's 96f (35.5c) and we have about 2 more hours before the sun goes behind the mountains. Avalanche, my Alaskan Husky, is outside playing with his jolly ball and running back and forth - stops from time to time to guzzle down some water before he goes back to running around; I've seen Avalanche out, sunbathing at over 100f. Sasha, my furry Siberian, is laying inside with me while I'm waiting for the sun to go down a bit more before we go out for a walk.
Husky's, from what I've seen are the ultimate adjustable dog. If it's hot they tend to laze around; if it's cold they tend to laze around ... well, maybe my Husky's are broken ...
The biggest problem, from what I've seen, is not the heat but the humidity. Since dogs cool themselves mostly by panting and evaporation, the drier the air is, the better they are able to maintain. Given that, depending on where you are, if the humidity approaches 50% or more, they're probably not going to do much except to wait for it to cool off.
Some obvious comments:
You don't want to exercise them during the heat of the day - period.
You *do* want to make sure that they've got plenty of fresh water available all the time.
You do want to know the signs of heatstroke in a dog. (google - there's more than you want to know)
Some things that people use are:
Frozen washrags, yeh, the same thing you use for a puppy who's teething.
Frozen "coke" bottles
Frozen kongs
Raised beds so they have some ventilation underneath.
My outside thermometer, in the sun, has started going down from it's high today of 135 (I said it was in the sun) and that's what it feels like when you're out in it. My dogs do okay, but none of us "push it" at all in this heat.
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“Properly trained, a man can be dog’s best friend.”
Corey Ford .