I keep them wet, all day. Any breeze will evaporate the water and keep them cool. l try to locate where the shade will be at the hottest time of the day, and fight for that parking spot . lol.
Don't leave tack on him all day. Loosen your girth in between classes and try to keep him in the shade and provide acces to water!
I show with other people that I know around me so we all get someone to carry a water bucket around with us so we can let them drink or put it on them if they get really hot
Lineament sponges or baths
keep him under shade if you dont have much time or are just about to show but if you do have time or you're finished with showing for a while untack him and rinse him off.:)
Always try to find shade if tied but stalls are easier and you can hang a fan in front of your horse.
If you have time, unsaddle and pour water on him or hose him off, then immediately scrape the water off.
We got our horse a canopy 😂😅
Wet him down at chances u have a let him drink water a walk around in shade