Some runners pride themselves on being four-season athletes, hardy enough to handle any weather conditions, come the sweltering heat and humidity, the torrential downpour of a spring morning, or sub-freezing temperatures and a bitter wind chill.
Committing to running regardless of the weather does have its benefits, as it hardens you to difficult conditions you might face on race day and sets a precedent of a no-excuses attitude.
After all, if you struggle with motivation, once you start bargaining with yourself regarding running in inclement weather, you can quickly find that you’re sliding down a slippery slope. Before you know it, you might realize you’re only heading out for your runs with the weather is picture-perfect.
But, when is it too cold to run outside?
Experts suggest you think twice before heading out for a run when temps dip below -18°F (-27°C). At that point, frostbite can set in within 30 minutes—meaning your workout could turn risky real quick. But honestly, who would want to go out in temperatures that frigid anyway?
While toughing it out can feel like a badge of honor, sometimes safety needs to come first. Let’s break down when it’s actually too cold to run and how to stay safe when braving the elements.
When Is It Too Cold to Run Outside?
Most runners want to know how cold is too cold to run outside.
Ultimately, there are no hard-and-fast rules or cutoff temperature under which all experts agree. It mostly depends on your personal tolerance, preparation, and comfort level.
Some runners can only handle running below freezing (32 degrees Fahrenheit or 0 degrees Celsius). Much below that, they have difficulty breathing or feel like their numb toes are going to fall off.
Runners with asthma, cardiovascular disease, diabetes, Raynaud’s syndrome, and low body fat may be particularly sensitive to running in low temperatures.
Other runners find that as long as they are properly equipped with the right running clothes and cold-weather running gear, they can reasonably handle running at any temperature, no matter how far below freezing the thermometer dips.
What Temperature Is Too Cold?
With that said, the American College of Sports Medicine1Hawkins, M. N., Raven, P. B., Snell, P. G., Stray-Gundersen, J., & Levine, B. D. (2007). Maximal oxygen uptake as a parametric measure of cardiorespiratory capacity. Medicine and Science in Sports and Exercise, 39(1), 103–107. https://doi.org/10.1249/01.mss.0000241641.75101.64 recommends that runners should not run outside when the air temperature falls below -18 °F (-27 °C) because tissue injury can occur in 30 minutes or less under these dangerous conditions.
It’s also important to be aware of the wind chill, as even seemingly mild wind speeds can significantly lower the “real feel” temperature on a cold day.
For example, when the air temperature is 30 °F (-1.1 °C), and the wind speed is 10 mph, then the resultant conditions will feel like 21 °F (-6.1 °C). You can calculate the wind chill here.
The Risks Of Running In The Cold
According to research,2Fudge, J. (2016). Exercise in the Cold. Sports Health: A Multidisciplinary Approach, 8(2), 133–139. https://doi.org/10.1177/1941738116630542 frostbite and hypothermia are the primary risks of running in the cold.
Severe frostbite is a direct freezing injury of body tissue that occurs with cold exposure that causes the skin temperature to fall below 28°F (-2°C).
Peripheral tissues away from the core that are particularly susceptible to vasoconstriction include the nose, ears, fingers, and toes. These areas are also especially prone to the risk of frostbite.
Runners who notice the early signs of frostbite, including cold, red skin (which will then progress to tingling, numbness, or a burning sensation), should immediately seek shelter to rewarm the skin.
Hypothermia, defined as a drop in core body temperature below 35°C (95°F), occurs when the total loss of body heat exceeds your physiological heat production. There are three grades of hypothermia, and unfortunately, severe hypothermia can be fatal.
Shivering is the early warning sign of hypothermia, but shivering ceases as the condition becomes dire.
Breathing can also be challenging in the cold air, with many runners experiencing a burning sensation in the throat or lungs. This can be especially problematic for runners with asthma. Breathing through a buff or balaclava can pre-warm the air and alleviate discomfort.
Things to Consider Before Running Outside In Cold Weather
To optimize your safety when running in cold weather, consider a few factors besides the air temperature when determining whether it’s too cold to run outside.
#1: Windchill
As mentioned, a major element that must be factored into your decision-making process about how cold is too cold to run outside is the wind chill.
Even relatively mild cold temperatures can be dangerously cold when the wind speeds are high.
Wind can damage exposed skin, and because the air temperature may be somewhat warmer, you have to factor in the windchill when evaluating the risk of exposing your skin to the elements.
#2: Precipitation
Of course, snow, sleet, or freezing rain can quickly make an outdoor run slippery and unsafe. Icy conditions are particularly dangerous, and you should run indoors on a treadmill if you have concerns about visibility and traction.
#3: Underfoot Conditions
Once precipitation settles on the road, it affects the underfoot conditions when you run. Even when roads are plowed, the shoulders and sidewalks are often covered in snow, slush, and ice, adding risk to your run.
Falling while running can result in an injury that could take you out of the game for weeks, so it is always best to err on the side of caution when road conditions are dicey.
Some runners find success with ice spikes or products like Yaktrax or FreeSteps6, which increase the traction of your running shoes on slippery roads.
#4: Darkness
Due to the short daylight hours, winter running often feels synonymous with running in the dark. Always ensure you are well-illuminated with reflective clothing and use a headlamp to light the trail or road ahead.
7 Running Tips for Cold Weather
If you’ve decided you want to test your inner warrior and brave the coldest of cold days down in the single digits and run outside, here are a few tips to make running in the cold safer and a bit more tolerable:
#1: Warm Up Indoors First
Sip hot tea and conduct your warm-up routine indoors so that you feel ready to go and somewhat warm before heading out into the extreme cold.
This can also prevent pulling a cold muscle and make the blast of winter air slightly more refreshing rather than brutal when you first head out the door.
Just be sure not to get too hot inside; sweaty and damp layers will make you feel more chilled once outside.
#2: Use The Right Gear
Your cold-weather gear can make or break your ability to run in the cold. Wear synthetic or wool long-sleeve base layers and windproof outer layers, and avoid cotton.
The general recommendation for what to wear running in the cold is to dress as if it were 20 degrees warmer outside and you weren’t running.
Overdressing can make you overly hot and sweaty, and once you’re damp, you will feel even colder. Using layers is ideal because they trap heat and can be removed if you feel too warm.
Wearing warm socks, gloves or mittens, a hat, and a gaiter is equally important to cover as much exposed skin as possible.
#3: Modify Your Route
Instead of embarking on a single, long out-and-back route or longer loop course, run small loops close to home or several short out-and-backs.
This will allow you to quickly head back inside if you feel too cold or display even the slightest signs of hypothermia or frostbite.
#4: Change Your Mindset
Instead of focusing on performance, focus on safety.
In other words, if you start feeling too cold or your toes and nose are numb, it’s time to head inside. Be happy and proud of what you did, and shift your priorities from finishing the workout no matter what to getting on some dry clothes and warming up.
#5: Hydrate With Warm Fluids
During and after your run, hydrate with warm (not hot) water or tea in a thermos to raise your core temperature.
#6: Take a Warm Shower As Soon As You Are Home
Once you’re home, take off your cold, wet clothes and take a warm shower. Be careful not to make the water too hot, as your perception may be skewed if your hands are numb, and the hot water can burn your skin.
#7: Consider the Risks vs. Rewards
Before heading outside in the bitter cold, consider safer, better options like running on a treadmill or cross-training at the gym.
Weigh the pros and cons and evaluate what you have to gain by running outside. Is it worth the risk?
Here are some beginner treadmill workouts you can try the next time it’s too cold to get out there.
Just watched a movie called Wind River. Boy, did they ever tell a doozie in that one about air temp!
Well, the whole thing was fiction anyway.
Intense movie. Deep winter. There is a winter 100 miler up there somewhere along a snowmobile track. You can run, ski, or fat bike it.
I’m always outside and people think I’m weird. I see people running in giant puffies and I just don’t get how they aren’t drenched in sweat. Makes me wonder how significant individual variation is. Would help me temper my recommendations. Good article, gonna send to a newer runner friend.
In Texas, running in the heat quickly acclimates you to hot temps, but I find it also greatly reduces my risk for muscle strains. Most of the injuries I’ve had in the past were directly related to colder temps. Doing any kind of speedwork when it’s super cold increases my chances of a strain or pull. I strained my right MCL years ago by jumping over some ice. I didn’t fall or slip either. I try to avoid running in the super cold to this day. Treadmill workouts and indoor cycling can be very productive. Just ask any top triathlete. I’m running my 7th Boston this year. Words to the wise…