The short answer
The feels like temperature on most weather apps is worked out for someone standing in the shade, so on a sunny run it reads low. Running at 5:30 per km (8:51 per mile) in full sun at 27°C (81°F), the feels like can reach 34°C (93°F). In cold wind, your own speed makes it feel colder.
Key takeaways
- Standard feels-like numbers assume shade; full sun can add several degrees on a run.
- Your running speed adds airflow, which cools you on a cold day and helps on a hot one.
- A tailwind matched to your pace cancels that airflow and makes a hot run feel hotter.
- Feels like isn't heat stress; use WBGT for safety decisions.
On this page
- What does feels like temperature mean for running?
- Why does your weather app's feels like read low on a sunny day?
- How does your running pace change the feels like?
- Does running make a cold day feel colder?
- Is feels like the same as heat stress?
- How should you use feels like to dress and pace?
- Questions runners ask
- Sources and method
Words this guide uses
- Feels like (apparent temperature)
- The air temperature that would feel the same on your skin as the real mix of temperature, humidity, wind and, sometimes, sun.
- Airflow
- The speed of the air moving past you, from your own pace plus or minus the wind.
- Wind chill
- How cold it feels on exposed skin when wind adds to the cold; the US National Weather Service uses it at or below 10°C (50°F).
What does feels like temperature mean for running?
The feels like temperature on a forecast is the air temperature that would feel the same on your skin, once humidity and wind are counted. For running, it's a useful guide to what to wear. But most versions are worked out for someone standing still, often in the shade.
A run changes two things: the sun on you and the air moving past you. Both can move the number by several degrees. This guide shows how, with worked examples. It's part of our running weather forecast hub, and Map your run shows feels like at your own pace for every kilometre.
Feels like is not the same as heat stress. Race medical teams use WBGT for that, as we explain below.
Why does your weather app's feels like read low on a sunny day?
Because the standard formulas leave the sun out. The US National Weather Service says its heat index was devised for shady, light-wind conditions, and full sunshine can raise it by up to 15°F (8°C).
Australia's Bureau of Meteorology is just as clear. Its published apparent temperature counts the wind but not the sun, even though the formula has a version that includes it. On a clear summer morning, a runner is out in exactly the sunshine those numbers ignore.
Here's what that does, at 27°C (81°F), 55% humidity, a light 10 km/h (6 mph) wind and full sun.
| Situation | Feels like, °C (°F) |
|---|---|
| App-style apparent temperature, no sun | 27.5 (82) |
| Running at 5:30 per km (8:51 per mile), shade, light crosswind | 27.0 (81) |
| Same pace, full sun, light crosswind | 34.0 (93) |
| Same pace, full sun, into the wind | 31.7 (89) |
| Same pace, full sun, wind behind you | 39.0 (102) |
| Standing still in full sun | 37.4 (99) |
In the shade, running barely changes the number. In the sun, the feels like at your pace is 6.5°C (12°F) above the app's, and more with a tailwind.
How does your running pace change the feels like?
Your pace makes its own breeze. At 5:30 per km (8:51 per mile), you move through the air at about 11 km/h (7 mph), and that airflow carries heat away from your skin.
The wind then adds to it or takes it away. Run into the wind and the airflow grows, so you feel cooler. Run with it at about your own speed and the air around you is almost still. That's why the tailwind leg of an out-and-back on a hot day feels hottest, even though it's the easier direction.
The RunFast engine counts this. It takes the wind at about body height, roughly two-thirds of the forecast wind at 10 m (33 ft), and combines it with your pace and direction on each stretch of the route.
Does running make a cold day feel colder?
Yes, on your skin. The airflow from your pace adds to the wind chill, so a cold, windy morning feels colder when you run into it than when you stand still.
The US National Weather Service's wind chill applies at or below 10°C (50°F) with winds above 5 km/h (3 mph). It's based on heat loss from exposed skin. Here is a 5°C (41°F) morning with a 15 km/h (9 mph) wind, for a runner at 5:00 per km (8:03 per mile).
| Situation | Feels like, °C (°F) |
|---|---|
| Standing still, no wind | 5.0 (41) |
| Weather service wind chill, 15 km/h (9 mph) wind | 1.7 (35) |
| Running, calm air | 1.3 (34) |
| Running into the wind | −0.2 (32) |
| Running with the wind behind you | 5.0 (41) |
So on a cold day, your app's number can read high for the first kilometres into the wind. Your body heat soon makes up for it. Dress for the coldest stretch, and plan a layer for the finish, when you stop making heat.
At a hiking pace on a high pass, the wind matters even more: see mountain ultra weather.
Is feels like the same as heat stress?
No. Feels like describes how the air feels on your skin. Heat stress (WBGT) measures how hard it is for your body to shed heat, using air, humidity, sun and wind together.
That's why race medical teams use WBGT for their flags. RunFast grades it Low below 18.3°C (65°F), Moderate to 22.8°C (73°F), High to 27.8°C (82°F) and Extreme above. Those bands match the American College of Sports Medicine's 1996 race guidance.
The two can disagree. At 27°C (81°F) and 80% humidity in shade, running feels like 28.9°C (84°F), barely above the air. But WBGT is 24.9°C (77°F), High, because sweat struggles to evaporate. Use feels like for clothing, and WBGT, plus official flags and medical advice, for safety.
How should you use feels like to dress and pace?
Dress for the feels like at your pace on the coldest stretch, and pace for the heat stress on the hottest. Check both before you leave.
On a hot day, look at the sunny stretches and any tailwind legs: those are where the feels like jumps. Our guide to the best time to run in hot weather shows how to pick the hour. If you're choosing kit, our what to wear running guide gives layers in °C and °F.
Questions runners ask
Does feels like include the sun?
Often not. The US heat index was devised for shady, light-wind conditions, and the National Weather Service says full sunshine can raise it by up to 15°F (8°C). Australia's Bureau of Meteorology publishes its apparent temperature without the sun, although the formula has a version that includes it. Your app may not say which it uses.
Why do I feel warm on a run when the feels like says it's cold?
Because feels like describes the air on your skin, not the heat your muscles make. Running produces a lot of heat, so you warm up within minutes even when the feels like is below freezing. That's why runners dress lighter than the number suggests, and why the first kilometre feels colder than the rest.
Is RealFeel the same as feels like?
It's a similar idea under a brand name. Different weather companies use different formulas, and some include the sun, wind and other factors while others don't. Compare the inputs rather than the label. For running, the key questions are whether it counts the sun and whether it counts the air moving past you at your pace.
What feels like temperature is too hot to run?
There isn't an agreed feels-like limit for running. Race medical teams use WBGT instead, because it was designed to measure heat stress. The American College of Sports Medicine's 1996 race guidance set its highest-risk band above a WBGT of 28°C (82°F). Use feels like to dress, and WBGT, official flags and medical advice to decide whether to run.
Do running weather apps show feels like at running pace?
A few do, as of September 2026. RunnersKit, an iPhone app launched in July 2026, offers a "RunFeel" adjusted to body, pace and distance. RunFast's free Map your run shows feels like at your pace, timed to each kilometre of your route. Most general weather apps show a standing-still number.
See the heat at your pace.
Drop in your route (GPX, FIT or TCX), pick the day and your pace, and see the feels like, dew point and heat stress for every kilometre, timed to when you’ll be there. Free, in your browser, no sign-up.
Sources and method
- US National Weather Service (2026). Heat index
- US National Weather Service (2026). Wind chill chart
- Bureau of Meteorology (Australia) (2026). Thermal comfort observations (apparent temperature and WBGT)
- Journal of Occupational and Environmental Hygiene (2008). Modeling the wet bulb globe temperature using standard meteorological measurements (Liljegren et al.)
- Medicine & Science in Sports & Exercise (American College of Sports Medicine) (1996). ACSM position stand: heat and cold illnesses during distance running
Worked examples use the RunFast engine's feels like at running pace. When warm, it is Steadman's apparent temperature with sun, in the form the Bureau of Meteorology publishes (AT = Ta + 0.348e − 0.70ws + 0.70Q/(ws + 10) − 4.25), with ws the airflow past the runner and Q a fifth of the sunshine on the ground; it never reads below the air. When cool, it is the wind chill formula applied to the runner's airflow. The "app-style" warm value is the Bureau's version without sun, with a 10 km/h (6 mph) wind; the cold value is the US wind chill with a 15 km/h (9 mph) wind. Warm case: 27°C (81°F), 55% humidity, sunshine 900 W/m², pace 5:30 per km (8:51 per mile), wind at body height taken as two-thirds of the 10 m wind. Cold case: 5°C (41°F), pace 5:00 per km (8:03 per mile). Imperial values are conversions.
Wes Thomson
Wes Thomson builds RunFast, which times the heat, humidity and dew point to a runner's own pace along the route, and its sister Windline, live wind forecasts for cyclists. Both run on the same forecast engine. He writes these guides with one focus: what the weather will do to your run, kilometre by kilometre, and how to plan around it.