I am one of the types of runners who love summer running.
I struggle with motivation and running in the dark and on slippery roads during the winter running season, but running in hot weather during the summer months rarely bothers me or affects my training.
However, I know that summer running can actually be more dangerous than running in the cold because extreme heat comes with the real risk of heat illnesses such as heat exhaustion and heat stroke.
Furthermore, running in hot weather can absolutely affect running performance, hydration needs, time to fatigue or rate of perceived exertion, and comfort regulating your body temperature.
In this guide to summer running in hot weather, we will discuss some of the challenges of running in the heat and humidity, how to run in hot weather, and the best summer running tips to help you stay safe and stick with your training plan through the summer months.
When is it too hot to run outside?
When you are deciding if it’s safe to run on a hot day, you need to pay attention to not just the high temperatures but also the humidity.
Humidity often plays a more significant role in the “real feel” when running in hot weather and the resultant risk of heat exhaustion and heat stroke.
High humidity makes running in hot temperatures even more taxing on the body because the moisture content in the air prevents sweat from evaporating readily.1Che Muhamed, A. M., Atkins, K., Stannard, S. R., Mündel, T., & Thompson, M. W. (2016). The effects of a systematic increase in relative humidity on thermoregulatory and circulatory responses during prolonged running exercise in the heat. Temperature, 3(3), 455–464. https://doi.org/10.1080/23328940.2016.1182669
As a result, the heat energy stays trapped in your body without getting released. This raises your core body temperature faster and more dramatically.
Although every runner will respond to running in hot weather differently, according to the Road Runners Club of America (RRCA), you should avoid running outside if the heat is above 98.6 degrees Fahrenheit and the humidity is above 70-80%.2Hot Weather Running Tips. (n.d.). Road Runners Club of America. https://www.rrca.org/education/for-runners/hot-weather-running/#:~:text=Understand%20heat%20index%20danagers%3A%20Avoid
How Do You Run In the Summer Heat?
Here are some of the best tips for running in hot weather or humid conditions during the summer months:
#1: Run In the Morning…Or Run at Night
One question new runners often have is: What are the best times of day to go running during the summer?
Ultimately, you want to choose the coolest part of the day to run during the summer months to reduce the risk of heat cramps and hot temperatures impacting your running performance.3Che Muhamed, A. M., Atkins, K., Stannard, S. R., Mündel, T., & Thompson, M. W. (2016). The effects of a systematic increase in relative humidity on thermoregulatory and circulatory responses during prolonged running exercise in the heat. Temperature, 3(3), 455–464. https://doi.org/10.1080/23328940.2016.1182669
It’s no surprise that the temperatures heat up once the sun comes out, so one of the best tips for summer running is to get your workout in the early morning or at night as the sun is setting or has at least left its peak position in the sky.
Keep in mind that morning running during the summer months generally means that you will be dealing with more humidity, as humidity is highest in the morning and then often decreases over the course of the day.
However, the air temperature and radiant heat from the sun should be significantly more forgiving if you go for an early morning run on what is expected to be a hot summer day.
The evening is the best time of day for a summer run if you live in an area with high humidity and extreme heat because you’re spared from the heat of the sun, and the humidity tends to be lower.
Make sure that if you are running in the pre-dawn hours or going out for a nighttime run, you should always wear reflective clothing and use a headlamp for safety.
#2: Find the Shade
Running coaches often recommend trail running when you are faced with a hot summer day.
It can be upwards of 10 to 15° cooler in a dense forest and area due to the canopy provided by the trees, which shields you from the sun’s rays.
You can also find shady areas on bike paths or tree-lined streets.
Staying out of the sun will help keep your core body temperature lower when you are running in high temperatures augmented by the sun’s rays.
#3: Wear Sunscreen
Make sure to protect your skin from UV rays and sunburn by wearing sunscreen (get a sweatproof, waterproof sunscreen with SPF 30 or more), a visor or running cap, and sunglasses.
#4: Choose Sweat-Wicking Running Clothes
Light-colored, moisture-wicking running clothes will help keep you cooler.
Breathable synthetic fabrics such as polyester are said to be sweat-wicking, which means they help pull moisture off of your skin and aid evaporation, which can help lower your core body temperature and prevent chafing, blisters, and the discomfort of running in sweaty clothes.
Consider running shirtless or just in your sports bra if it is comfortable and appropriate where you train.
#5: Pre-Cool Your Body
One running tip for summer running that I have incorporated into my own hot weather running routine is to pre-cool my body before I head outside.
I don’t have an actual ice vest, though you can buy one, but I will put a large ice pack meant for back pain on my back or stomach for 10 or 15 minutes before heading outside.
This helps lower my core body temperature so that as I get through the warm up of my run, I am actually starting in a chilled state so that I don’t overheat as quickly.
#6: Wear an Ice Bandana
Another great tip for sun protection and keeping cool when running in extreme heat is to soak a bandana in ice water and then freeze it before you go running in the heat.
Then, take out the stiff, frozen bandanna when you head out the door and tie it around your neck. It will feel really cold but will eventually melt and mold to your body.
It also serves a double purpose of protecting your skin from sunburn.
#7: Get Hydration Running Gear
Hydration is always important, but especially during hot weather running because you are going to lose more fluids from sweat.
Don’t rely on being able to get your hydration at water fountains because you never know if the water fountain is out of order or if you need extra fluids earlier on in your run.
A good hydration pack or handheld water bottle is an essential piece of hot weather running gear.
I love the Black Diamond Women’s Distance Hydration Vest 4L pack for even short summer runs (it comes in a men’s version too!).
#8: Carry Ice Water
Fill your hydration pack or water bottle with ice water or a cold sports drink with electrolytes so that your fluids are more appealing to drink and help cool your core body temperature while you keep your hydration levels up.
I often bring one water bottle that has ice water (and drink this first) and one water bottle that is completely frozen with ice water or a sports drink so that it remains cold as it melts for the later miles of my run.
#9: Run By Feel
Many runners prefer to train by pace, and pay attention to their GPS watch as if every interval and split makes or breaks a run.
Running by feel can be a safer option when running in the summer heat.
When you run by feel, you listen to your body, respecting its needs while still getting a quality workout.
#10: Do a Cool Down
Make sure to do a thorough cool down to help guide your heart rate back down to resting levels and prevent muscle cramps from shocking your system by suddenly jumping in a cold shower.
Once you finish your run, do a few minutes of walking to reduce the risk of muscle cramps and to give your body time to stop sweating profusely, and then go inside where it is cooler.
Start rehydrating with ice water and/or electrolytes.
I often suggest having a smoothie or even freezing sports drinks into popsicles so that you are getting your hydration and post-run carbs and electrolytes while bringing down your core body temperature with an appealing, cold treat.
#11: Run Inside
With extreme heat, consider running indoors on the treadmill or doing the cross-training workout inside where you can be in a climate-controlled environment with air conditioning.
It is not worth risking heat-related illnesses such as heat cramps, heat exhaustion, or heat stroke just so you can get in your outdoor running workout.
#12: Shorten Your Run
You may need to shorten your run and deviate from your training plan during the hottest summer days.
Remember that although it’s tempting to stick with your training plan when you are preparing for an upcoming 5k, half marathon, or other big race day, it is always more important to prioritize your safety with heat-related illnesses.
To ensure you keep well-hydrated, check out this next guide:
