As someone who has experienced a heat dome here in BC, you have my sympathies. It's soggy and cool here right now, and while depressing, it's not as depressing as being baked alive.
I never really had an excuse to look into temperature data in Mexico and I'm honestly a little surprised by some of the numbers
It looks like Mexico City is likey to have temperatures of about 35c (95F for Americans like myself) Which does seem like it will be their all time highest recorded temperature there.
I knew they're at a pretty high elevation, but I guess I kind of figured Mexico=hot and that even their relatively cooler areas would be roughly on par with the high temperatures I'm used to here in Pennsylvania.
Because 95, while still a pretty damn hot day, isn't exactly news-making around here (this early in the year it definitely would be, but in general it would be a little bit unusual if we don't hit that temperature at least once or twice over the summer, even 100+ isn't unheard of.)
Don't get me wrong, I'm not trying to downplay the situation they're experiencing, 95 is absolutely the kind of temperature that can kill people if they don't have the infrastructure to escape the heat, and they don't because the temperatures aren't supposed to get that hot there. I'm more pointing out my own ignorance of Mexican climate.