High summer is here. In lots of locales, the temperature is up in the 90s and the humidity is close behind. So when is it too hot to ride?
There's no real answer to this question. People and horses have different heat tolerance, so deciding to ride in the heat is a personal decision. However, there are a couple of things to be aware of.
Horses (and humans) sweat to cool themselves. When its very humid, the impact that sweating has is lessened. A rule of thumb is if the temperature and the humidity combined are above 180, riding isn't recommended.
If you do, though, watch for signs of dehydration and heat stroke in both yourself and your equine partner. Profuse or no sweating is one sign, along with elevated pulse and body temperature. White instead of pink gums and "sticky" skin that doesn't bounce back when you pinch it are both signs of dehydration. To cool your horse down quickly run cool (not cold) water on the veins on the insides of his legs and over his back and chest.
Another good rule of thumb: If it's too hot for you, it's too hot for your horse.