06/13/2026
Don't forget it's way to hot to work horses here today. Stay safe and keep your equine friends safe! You should stop working your horse when the combined air temperature (°F) and relative humidity (%) exceeds 150. At this threshold, a horse’s natural cooling mechanisms become compromised, and doing intense work puts them at a high risk of dehydration and heatstroke.The American Association of Equine Practitioners (AAEP) uses a widely accepted guide based on the "Rule of 150" to determine if conditions are safe:Temperature-Humidity Index (THI)Below 130: Normal riding and turnout are safe. The horse can effectively regulate its body temperature.130 – 150: Use caution. Monitor the horse closely for heavy breathing, lethargy, or excessive sweating.150 – 180: Use extreme caution. A horse’s ability to sweat and cool down is greatly reduced. Adjust workload, take frequent breaks, and provide access to water.Over 180: Do not work your horse. A horse’s cooling systems become largely ineffective, and any exercise can be life-threatening.Real-World ExamplesAir temperature 85°F + 65% humidity = 150: Extreme caution is required; it is generally unsafe to work them hard.Air temperature 95°F + 60% humidity = 155: You should stop or postpone riding completely.How to Keep Your Horse SafeRide early or late: Try to work horses in the cooler morning or evening hours.Sponge and hose: Continuously hose your horse with cool water and scrape it off to help them shed body heat quickly.Provide fans and shade: Ensure they have access to free-choice water and well-ventilated, shaded areas when resting.For a more detailed breakdown of how humidity impacts heat stress, you can check out the Equine Heat Index Tool by Mad Barn or the University of Georgia Equine Program.