Yeah you either ride early or late, around here. And opt for the shady pasture or the covered or indoor. I miss the indoor with fans honestly, but any shade is a blessing!
Alcohol sprays, or just hosing the horse off entirely and standing them in front of the fans while tacking up helps too. They’re pretty cool and dry enough to saddle quite quickly. Obviously at a certain temperature + humidity it’s just not going to happen, but for our average summers, it’s possible to ride most days without risking the health of horse or rider. No drilling or really intense schools, just get one or two things done and call it quits.
The other thing we do is cut the cool-down short. Get off the horse and pull tack, hose them off and THEN go walk. No sense in walking a hot sweaty horse under saddle forever when you can get out of the sun and cool them off way quicker by getting OFF. A nice long hack after a ride is best saved for when it’s cooler and breezier.
ETA for shows it’s the same. Minimal warmup, just wtc for a bit and pop and fence and go in. No standing around waiting in the sun to watch others go, send the horse back. Alcohol and water in a spray bottle, cool water for the horse, wet towels in a cooler, and scratching when it’s just too hot and humid are all ways to show in the summer down here. And people pick the venues that make reasonable accommodations with cooling stations and schedule changes and covered rings. It means a lot of your local/unrated things don’t run in the summer, which is fine by me.