There is something in what you say, charlotta, but North Americans are probably better equipped to cope with sudden heat waves than almost anywhere else on the planet, what with water on tap in every home, air-con, etc, etc. I don't agree that people who live in the tropics "are better able" to cope with the heat. They cope because they have to. I'm not sure I ever acclimatised to the tropics. I learned how to tolerate the heat and not to be overcome by it but it was early March I moved back to Britain and I instantly remembered what it felt like to be actually comfortable.
Excessive cold is actually far more dangerous than heat and cold snaps in Europe and North America cause far more deaths.
To sit out in that heat is ridiculous! I lived in Singapore when I was a child for a few years and we never used suntan lotion just stayed in the shade when we could and we didnt burn, and my two sisters were white blond so very fair skinned (think I was the milkmans ), but it was a long time before we all became aware of the dangers of the sun.
I think that most White Americans are of European stock and therefore more able to cope with cold weather rather than hot weather. I have heard of friends in Texas who are definitely not sitting in the sun but have not been out of the house for weeks. The people of Thailand are able to cope better with the heat, it is known fact that if you are long enough in that sort of climate you acclimatise. It is the sudden heat, the jumps in temperature which we Europeans or White americans find so trying.
AIBU to think that people in the US should be able to cope with a heat wave? BBC news says temps have been getting up to 37°C. I, and several million other people, worked in temperatures that high in Thailand all the time! Billions of people in the tropics live with those sorts of day time temperatures ALL THE TIME! The pictures in the news item show people sitting in the sun. How stupid is that? I never used sun cream and never got sunburned (though I did tan a little) when I was in Thailand because I did what the Thais do — stayed in the shade unless it was absolutely essential to be in the sun, and even then you got out of it as soon as possible, you wore a hat and, in short, you were sensible.