How hot is too hot to ride? SmartPak veterinarian Dr. Lydia Gray has the answer.
From the SmartPak Blog:
Out here in the Midwest, our summers get seriously hot and humid. I personally don’t mind the heat, but I worry that it’s too much for my horse. He sweats a lot when it gets above 80* and even though his attitude and energy seem pretty normal, I worry that he’s getting overheated and I don’t know it. Is there any information on when is “too hot” to ride? Also, if I’m concerned about my horse, how can I check if he’s overheating, and when should I call the vet?
That’s great that your horse sweats a lot above 80 degrees! It means that he is acclimated to the environment and that his body has made adjustments—such as increasing the sweating rate and starting to sweat at a lower temperature—to adapt to the warmer weather. It’s also great that you notice at what temperature your horse’s cooling mechanisms really begin to kick in and that, even though he’s working and sweating, he still feels good.
To answer your first question, although a specific show, race, or other horse event may decide on an upper limit above which their activity may be modified or even cancelled, there’s really no hard and fast rule among the horse community about when it’s too hot to ride. One of the reasons is that temperature alone isn’t that great of an indicator of how well a particular horse may deal with the heat.
Read the rest of Dr. Gray’s answer here.