We’ve been many times in August. I always say afterward, “Never again!”… but never say never!

(Kinda hard to pass up a great deal!) As a pp mentioned, there are also a lot of thundershowers, as well, often in the late morning or afternoon, which isn’t too, too bad unless everything shuts down (even boats, rides, can be stores, etc.).
Today there are some things I’d bring that I didn’t have in the past, like a cooling hat (run it under water and put on head), a cooling towel (same as hat but for neck), even an umbrella meant to block the sun, etc. I’ve found that as I’ve aged it’s gotten harder and harder to regulate my internal temperature (and in fairness, I also have a medical condition and am on some meds that make it worse). So if you’re younger, it’s sometimes easier, though my daughter’s only in her late 20s and even she’s saying it’s harder now!
I’m talking days that are high 90s but “feel like” low 100s - brutal!
I remember one day making it about halfway around World Showcase when I just couldn’t tolerate it anymore, even after going in places to cool off. We booked it back to the resort and I stood under a waterfall in the pool for a half an hour before I really cooled down! Awful! YMMV!