Summer’s here, and runners have traded their rainy-day running outfits for shorts and t-shirts. California can reach some extreme temperatures, so outdoor runners usually start early in the morning or late at night. So, what do you do if lunchtime is your only opportunity to squeeze in a run? Well, hopefully you’ll head to the club to log your miles on a treadmill in the comfort of our AC—but if your heart is set on running in the heat, keep reading.



Is it too hot to run outside?

This question isn’t as simple to answer as checking for a certain number on the thermometer. Humidity levels make a huge impact on how your body feels during a workout outdoors.


When you check the weather, take note of the relative humidity as well as the temperature—then you can view the Heat Index Chart at the National Weather Service. This will tell you how it will actually feel outside—for example, if the air temperature is 100°F and the relative humidity is 55%, the heat index will be 124°F. Note that this chart is actually for shady locations, so if you’re running in direct sunlight, the heat index value can be increased by up to 15°F.


Some weather apps even do this work for you automatically—you’ll see an actual temperature listed, along with what it “feels like.” 


Here’s how the National Weather Service outlines the risks associated with prolonged exposure or physical activity:

80°F - 90°F: Caution. Fatigue possible.

90°F - 103°F: Extreme caution. Heat stroke, heat cramps, or heat exhaustion possible.

103°F - 124°F: Danger. Heat cramps or heat exhaustion likely, and heat stroke possible.

125°F or higher: Extreme danger. Heat stroke highly likely.



Tips for hot-weather running:

  • Wear sunscreen.
  • Stay hydrated.
  • Be careful! Remain vigilant for any signs of heat sickness including headache, dizziness, nausea, weakness or muscle pain.



Remember, no workout is worth risking heat sickness. When the day gets too hot, it’s a sign to take your exercise indoors. We have all the shade and air conditioning you could want at our clubs!