I love Michigan but the extremes of the weather – bitter cold in the winter and high heat in the summer – play havoc on horseback riding lessons. Many of our therapeutic riders cannot tolerate the extreme temperatures so they need to miss those days and that is very understandable.
When it’s cold, most of us can add layers and turn on the barn heaters to take the chill out of the air. But what about the heat of the summer, especially those humid muggy days? What is the guideline for too hot? In the winter I can easily say we are closed if the wind chill is below 10 degrees. But I just can’t use the heat index in the summer.
We all know it’s not the heat, it’s the humidity that does us in. And it’s the same for the horses. Once the humidity goes above 75%, the horse has a hard time dissipating their body heat, so we need to take precautions.
The best way to determine ride days is to use a heat STRESS index. It’s a little more complicated than listening for the heat index because it takes into account the temperature, humidity and wind. The formula is:
Temperature + Humidity – Wind =
Heat Stress Index
Let’s look at two 90 degree days:
Day one has a humidity of 70% and no wind. The heat stress index is: 90 +70 – 0 = 160.
Day two has a humidity of 45% and the winds are 10 miles per hour. The heat stress index is: 90 + 45 – 10 = 125.
Now that you know the heat stress index, you can decide whether you could ride.
The rule of thumb is:
|Heat Stress Index||Less than 130||130 – 170||Over 170|
|Decision to ride||Let’s Ride!||Ride with caution. Watch for heat exhaustion and cool the horse regularly||Do not ride.
Most likely the humidity will be over 75% and the horse will not be able to cool itself properly
Of course, you can still have fun with you horse on these blistering hot days.
Ours love a bath or just running under the sprinkler!