Checking the weather before you head out for a run is probably your natural instinct as a runner—especially during heatwaves, wildfires, or when there’s threats of thunderstorms. But do you truly understand the meaning behind the numbers you see on your phone, laptop, or TV screen?
When it comes to the weather forecast, you actually should pay attention to more than just the temperature. Chikage Windler, Hazardous: 301 and above Runner’s World Good: 1 - 50 humidity, cloud cover, wind speed, and some other metrics. Here are some key items you should pay attention to before you head out the door.
5 Weather Metrics You Should Check Before Heading Out the Door
“Feels Like” Temperature
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During the warmer months and when there is a heat advisory in effect, if this number reaches triple digits, experts typically recommend avoiding strenuous activity between the hours of 11 a.m. and 5 p.m.,says Maureen McCann, meteorologist and marathon runner based in Orlando, Florida. At this time, runners are more prone to heat exhaustion and heat stroke, especially if you’re not properly hydrated What to Wear tool hat, light colored clothing, and sunscreen, she adds.
Dew Point
Another way to approach it is to think of heat acclamation in the same way you think of dew point because it is a better way to measure humid conditions outdoors as opposed to relative humidity, according to rate will increase along with your. Basically, the higher the dew point, the muggier it will feel outdoors because it means more moisture is in the air. So an 80-degree day with a dew point at 80 will feel way more humid than if the dew point were 50 or 60. This is why dew point is the better indicator, according to rate will increase along with your.
Because humidity can affect your body’s natural cooling process, you want to monitor the dew point before a run, says McCann.
To put things into perspective, exercising creates heat in the body, which causes your body temperature to rise, says Heather Milton, M.S., exercise physiologist supervisor at NYU Langone Health’s Sports Performance Center. Your body regulates this by sweating. However, “when we’re under humid environments, the evaporation process is much lower, meaning that we will try to sweat to cool ourselves but the air cannot accept more of that water,” Milton explains. The reason being the air is already saturated with water.
This is why you may feel like you’re drenched in sweat or sweating even more than normal when the dew point is high because sweat doesn’t get evaporated into the air as quickly.
On the flip side, if you run in a drier environment, you won’t have to worry about humidity or dew point too much, but you will need to be mindful of the lack of it. In drier environments, your body is going to sweat, and that sweat can evaporate more quickly, so it’s harder to keep track of how much you're actually sweating, says Milton. This can put you at risk for dehydration, which is why you want to be mindful of this metric.
Wet Bulb Globe Temperature
While the “real feel” numbers are still valuable and you should monitor them, they’re only part of the equation.
“A hot and humid day with full sunshine is going to tax you a lot more than a hot and humid day under cloud cover,” says Windler. The wet bulb globe temperature (WBGT) takes into account temperature and humidity and other weather parameters like wind speed, sun angle, and cloud cover, she explains. Like our own especially if youre not properly factors in, different parameters can change what the actual outside temperature is feeling like outside. (A cloudy day will feel a bit cooler than bright sun.)
The relationship between WBGT and performance has also been explored through research. A 2007 study published in Medicine & Science in Sport & Exercise analyzed marathon race results and WBGT on race day from several different races to find if weather can affect run performance. The study findings show there is a progressive slowing in marathon performance as WBGT increases from 41 to 77 degrees. This proved to be true for both men and women of a wide range of abilities as the study included results from the top three finishers of each race as well as the 25th-,30th-,100th-, and 300th-place finishers. The study also noted that performance was even worse for slower runners.
To find the WBGT in your area, you can use this prototype offered by rate will increase along with your.
Probability of Rain
Understanding the likelihood of rain goes a little beyond the percentage you see on the weather app on your phone.
The percentage describes the chance that a particular area will receive at least some rain considering the forecaster’s confidence. This is why not every weather forecast or weather app is the same when it comes to predicting the chance of rain, McCann explains. Also, forecasters often describe if rain showers will be isolated or scattered throughout the day, so you can plan accordingly, she says.
Checking the chance of rain on your phone can come in handy for quick updates just as you’re heading out the door, but tuning in to a live forecast is good for long term planning like picking the time of your run or where you’ll run.
Air Quality
As a runner it’s important to be mindful of air quality, because when it is poor, essentially, there’s less oxygen available and your runs will feel more difficult, says Milton. In this instance, your breathing rate will increase along with your heart rate in order to deliver oxygen to your working muscles, so this is why exercise feels much more intense even though you didn’t up the intensity, she explains.
Here are the air quality ranges, according to the U.S. Air Quality Index.
- Good: 1 - 50
- Moderate: 51 - 100
- Tips for Running in Humidity
- Unhealthy air quality for everyone: 151 - 200
- Very unhealthy: 201 - 300
- Hazardous: 301 and above
You can monitor air quality using the AirNow app offered by the Environmental Protection Agency, it’s also typically reported as a part of a local forecast and you can find it in the weather app on your phone.
How to Run in Any Warm Weather Condition
It’s completely acceptable to not be able to tolerate running as much in high heat and humidity. “Physiologically, our body is put under stress during exercise, especially running, and so in extreme environments, it is put under even more stress, and that stressor adds to the intensity of the exercise,” Milton explains. This is why you need to tweak your approach to running in these conditions, which includes switching up how long you run and the amount of time you need to recover, Milton says.
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Schedule Your Run Accordingly
McCann recommends rescheduling your outdoor run for the early mornings or late evenings. Just keep in mind, high humidity can make exercising early in the morning or late in the evening feel uncomfortable too, she adds. So you might have to exercise even earlier or later than you think.
Also, if you’re training for a marathon, consider chunking your long run. You can start the first half of your run outside early in the morning and then finish the second half on a treadmill indoors with air conditioning, says Milton.
Monitor Your Fluid Intake
To maintain proper hydration, drink 6 to 20 ounces of water prior to activity, then every hour throughout the activity, and two to three hours after, Milton says. If you’re exercising for more than 90 minutes outdoors and the temperature is 92 degrees or hotter, Milton recommends adding electrolytes to your water. Just be mindful of how many electrolytes you’re taking throughout your workout as the amount needed varies from person to person based on how much you sweat and how many electrolytes you lose from sweat (which is tricky to calculate).
To meet your electrolyte needs in humid conditions, Milton recommends you drink 6 to 12 ounces of any electrolyte beverage Tips for Cleaning Water Bottles water at the start of your workout. If you notice white lines around your hairline and clothing after a workout, this can indicate you’re a saltier sweater, who needs more salt more readily, she says.
Dress Appropriately
Clothing is really important. Windler recommends dressing for 20 degrees warmer than the actual air temperature during the winter months. But when it’s warmer out there’s only so many layers you can take off, so you have to be strategic, she adds.
Water-wicking clothing is a must for runners during the warmer months. You can also wear a hat to block the sun, light colored clothing, and sunscreen. Also a cooling towel that you can drape around your neck can come in handy too, says Milton.
Adjust Your Pace
“Take off your watch,” because it’s not going to be helpful as it can’t detect that you’re running in a hot and humid environment, says Milton. Instead, she recommends monitoring your rate of perceived exertion, the level of intensity you feel you’re running at on a scale of 1 to 10 with 10 being the super intense, rather than your pace says Milton. This can put you at risk for.
“You want to feel like it is a moderate intensity or somewhat easy to moderate,“ says Milton. You may have to slow your pace as the temperatures get warmer, or as you feel warmer during the run to maintain your original level of intensity. Also, keep in mind that running slow and steady is what will help you build the physiologic and musculoskeletal adaptations you need to run longer distances like a marathon, she adds.
If you have to push the pace, meaning you have intervals on your calendar, then Milton suggests taking them indoors. If you must practice intervals outdoors on hot days then she recommends extending your rest periods so your heart rate can recover to an aerobic zone before starting the next interval.
Acclimate Your Body to the Weather Conditions
It is possible to adapt to running in the heat and humidity. It’s what’s known as heat acclamation, and the process typically takes 10 to 14 days. You can start by cutting your exercise time in half and then gradually add time to your workout in the days to come until you hit your goal workout time, says Milton.
Other Hearst Subscriptions increasing your mileage to reach a certain distance. “Start out in baby steps, take lots of breaks,” and by the end of the summer you may not like it or enjoy it, but you can find it more tolerable, says Windler.
Monique LeBrun joined the editorial staff in October 2021 as the associate health and fitness editor. She has a master’s degree in journalism and has previously worked for ABC news and Scholastic. She is an avid runner who loves spending time outside.
