How Cold Is Too Cold to Run?

Maybe a polar vortex has drifted over your location this week. Maybe you feel a little unnerved by a winter chill. One time, when I was living just on the other side of Lake Michigan from Chicago, our wind chills will drop into the negative 40 Fahrenheit range. For even the heartiest of runners, the dangerously cold wind chills raise the question “How cold is too cold to run outside?”

If you ask runners this question, the answers will widely vary. I posed the question to my Instagram community and received answers ranging from 40 degrees to “frostbitey cold.” 

Some runners love being out in 10 to 20-degree temperatures; however, some runners refuse to run in anything below freezing. Other runners claim that there’s no such thing as bad weather — just bad gear.

But what about beyond preference? Is there actually a threshold at which it is physically unsafe to run? Is there an actual answer to the question: “When is it too cold to run?”

(All references to temperature in this resource are in Fahrenheit unless otherwise noted).

What Happens When Running in Below Freezing Weather?

Performance Impact

You cannot expect to run the same pace when the wind chills drop to 0 degrees or below — even if you are properly dressed. In frigid conditions, your body prioritizes blood flow to your core in order to protect your vital organs. As a result, your extremities — including your working muscles — receive less blood flow, and the blood vessels constrict. Without normal blood flow to your working muscles, you cannot expect to run like you would in milder temperatures.

How Cold Is Too Cold to Run?

Health Impact: Hypothermia, Frostbite

Beyond performance consequences, health concerns arise in frigid conditions. Sub-zero temperatures pose risks such as hypothermia and frostbite.

  • Hypothermia becomes a concern in negative temperatures. Hypothermia occurs when your core temperature dips below 95 degrees. In frigid sub-zero temperatures, the risk of hypothermia occurs within just 30 to 60 minutes — the average amount of time you would spend on a run. Wind chills reaching well below zero can increase the risk of hypothermia. The symptoms of hypothermia can range from extreme shivering and blue fingernails (in mild cases) to shallow breathing, exhaustion, confusion, loss of coordination, slurred speech, and a weak pulse. 
  • Frostbite poses another risk. The colder it is, the higher the risk; the risk of frostbite increases when the temperatures drop below minus 5 degrees Fahrenheit/-20 Celsius. Once the wind chill reaches below minus 16 degrees, frostbite on exposed skin can occur within 30 minutes. The colder it gets, the shorter amount of time it takes for frostbite to happen.

Tips for Running in Negative Temperatures

If you are going to run outdoors in very cold temperatures – whatever those are to you – optimize your safety and performance with the following tips:

1. Consider the Windchill

The windchill matters as much as the actual temperature. There is a significant difference between 10 degrees and sunny with little wind and 10 degrees but overcast with 20mph winds. When looking at the conditions, always consider the wind chills. The wind chills are indicative of how your body will actually feel. If it’s cold, your body will need to work harder to stay warmer compared to the same temperature with no wind.

2. Weigh the Risks and Rewards

What I always consider in any aspect of running are the risks versus the rewards. What are the risks of running outside in the extreme cold? Do they outweigh the benefits of a single run (or, in very bad conditions, a week of training)?

So, can you run in 20 degree weather? Is it ok to run in 15 degree weather? Sure. But ultimately, you have to respect your personal comfort zone. Just because someone on Instagram ran in 10 below F temperatures doesn’t mean you have to. If you do not feel comfortable running outdoors in the cold, stick to the treadmill or indoor track, or cross-train instead. There is no shame in using the treadmill! And if the temperatures are so far below zero that you do not even want to leave the house, take a rest day or do an indoor workout from the warmth of home.

3. Warm Up Indoors

You do not want to break a sweat in this warm-up since anything damp against your skin can increase the risk of hypothermia. The purpose of an indoor warm-up is to start sending oxygen-rich blood to your working muscles and improve your range of motion before you head into the cold.

Try a simple warm-up such as this pre-run warm-up or one of these dynamic warm-ups for runners. Do your warm-up right before you head out the door.

How long can you be outside in 0 degree weather? The U.S. National Weather Service says that exposed skin can freeze in as little as 30 minutes, so allotting that time for your run rather than your warm up can be useful.

4. Dress Appropriately

When running in below freezing weather, you need to take precautions in how you dress. Wear wicking layers that will keep you warm and help you stay dry. If it is very windy, top off with a wind-resistant jacket. Cover up as much exposed skin as possible to prevent frostbite. Mittens, neck gaiters, hats, tall socks, and balaclavas can protect sensitive areas. Even if it’s not very sunny out, sunglasses or even ski goggles can protect your eyes from the sting of the cold and wind. Duct tape your shoes to prevent heat loss.

How Cold Is Too Cold to Run?

5. Eat Well and Hydrate Before Your Run

When you run in very cold temperatures, you are asking a lot of your body – so provide it with the resources it needs. While running in the cold does not necessarily burn more calories, an empty stomach is not to your advantage. Running in the cold relies more on aerobic metabolism using carbohydrates (vs aerobic metabolism using fats). Your body needs available energy to run in the cold. 

Hydration is essential also. The cold can mask thirst, but the dry air can be dehydrating. As you run in dry air, your body loses fluids as it works to humidify the dry air.

6. Run by Time Instead of Distance

The combination of the cold, wind, ice, and snow will slow you down. If you run 5 miles in 45 minutes in normal conditions, then run for 45 minutes – without worrying about pace – in the cold conditions. Training by time ensures you get the same benefits of the run (45 min at an easy pace is the same no matter how far you go!) while also accounting for conditions affecting your pace. 

Easy runs are a better option in the bitter cold. Snow and ice often accompany sub-zero temperatures. Even if you find a clear stretch, the cold can increase the risk for pulling a muscle or tendon.

7. Be Flexible in Your Training

Your training plan should not dictate your life. During bad winter weather, adjust your training plan as needed. If the weather is ideal one day, try doing your long run or hard workout that day. If it’s too cold to run outside, either take a rest day, cross-train, or adapt your run for the treadmill.

Try one of these treadmill workouts for runners or, if you are training for a race, these race-specific treadmill workouts. If you have to do a long run, try these tips for surviving a long run on the treadmill

8. Be Extra Thoughtful When Running in the Cold with Dogs and Kids

If the wind chill reaches below zero, leave your dog at home. They are more sensitive to the cold than humans, even with booties and a jacket. Sub-zero temperatures are certainly not the weather to take an infant or toddler out in a jogging stroller. Just because you can bundle up and tolerate bitter windchills as an adult doesn’t mean your pets or child can. 

So, How Cold is Too Cold to Run?

Personally? After examining the evidence, I would not run in anything colder than a negative 5-degrees wind chill. Running below freezing is okay, but any colder than that negative 5 degrees wind chill is not worth the risk of frostbite and hypothermia. Others will have different conclusions than I do – some will head indoors much sooner and some will run in even colder conditions.

Want more science-backed advice, on everything from what temp is too cold to run outside to muscle cramps and more? Listen to the Tread Lightly Podcast! With weekly releases, the podcast is available on Apple, Spotify, Amazon Music, and Google Play.

Disclaimer: I have a MS in Applied Exercise Science with a Sport Nutrition concentration and am an ISSN certified sport nutritionist. However, the above is not medical advice. If you have special concerns such as hypertension or certain medications that alter sodium levels, consult a registered dietitian or a medical professional.

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21 Responses

  1. With the temps that the Midwest is getting right now, my butt would be inside on the treadmill or track. It’s just not worth it to feel miserable. Not to mention how hard it is to warm up afterwards. I’ll run in single digits with a wind chill below zero but it depends on the distance and what my goal is for the run. Easy running is all that I’ll do outside in frigid temps. Stay warm!

    1. Thank you! It’s so cold here that my gym is even closed, so even the track and treadmill are not an option here! Warming up after a frigid run is the worst part – it can be harder than the run itself!

  2. My threshold for longer runs is around 10F – any colder than that, and I’m just too uncomfortable in the later miles for it to be worth it. I’ve done some shorter runs when it’s been in the single digits, and with enough layers I’ve been ok – but I feel like the Michelin man in those cases 🙂

    Minnesota is so cold today that they even suspended our mail service (current air temp this morning is -28!!). Even though I don’t love the treadmill, I’m thankful my gym has remained open so far!

  3. As much as I love seeing photos of runners with frozen eyelashes (so pretty, really) I just can’t imagine running in the negative temperatures. Fortunately, that will never be a problem for me! I’m so glad I live in a desert! Stay safe when you run in this crazy weather!

  4. I usually run outside as long as the streets are not icy. Monday is was a feel like -6, but there was very little wind, and it was fine, I was actually overdressed. The wind plays a much larger role for me in the winter than the temp does. I’m in NE Ohio, so we’re dealing with the polar vortex. My butt was at the fitness center running countless laps around the small indoor track.

  5. 10 degrees including the wind chill is kind of my threshold also. Wind speed is really the more critical factor though. If it’s over 15 mph and less than 32 degrees it can be miserable that one direction. I love being outside and if the paths aren’t clear enough to run I’ll snowshoe or cross country ski. Otherwise I will be inside. My gym is closed today too but I did strength and cross training at home rather than go out in the -40 degree wind chill.

  6. Really great tips! I think we’re going to have some negative degree wind chills over the next couple of days! Wearing the right amount of clothing and protecting the extremities is so important with the weather so cold! I need to find some good wool socks to stay warm out there!

  7. I have definitely run in some super cold temps when I wad training for Boston which is sometimes not fun. The gear is definitely key as well as hydration and fueling beforehand and during. Time to layer up!

  8. These are all great tips. Personally, I can’t take running on the treadmill or in the gym, so outside is just always what I do – hot or cold. Living in Minnesota, where a below zero windchill is pretty normal in the winter, I’m just used to it. I would say that the temps we’re having today (-27 with a -51 degree windchill) are too cold for me to run outside, but honestly, anything up to a -35 windchill is okay with me. You’ve just got to make sure every little bit of you is covered, your layers are windproof and warm, and you don’t stay out too long!

  9. It’s never too cold for running. I’m the person who runs in t-shirts and shorts in winter too unless the temperature drops below 15F.

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