How much does wind slow you down?
Even on a calm day, part of your energy goes into pushing air out of the way. At typical running speeds that is only a few percent of the total, but air resistance grows with the square of the speed of the air flowing past you. Run into a headwind and that air speed is your running speed plus the wind, so the cost climbs quickly.
At the same effort, a 5:00/km (8:03/mile) runner loses roughly:
| Wind at running height | Headwind pace | Tailwind pace | Out-and-back average |
|---|---|---|---|
| 10 km/h (6 mph) | 5:15 /km (+15 s) | 4:53 /km (−7 s) | +4 s/km |
| 15 km/h (9 mph) | 5:26 /km (+26 s) | 4:53 /km (−7 s) | +9 s/km |
| 20 km/h (12 mph) | 5:38 /km (+38 s) | 4:50 /km (−10 s) | +14 s/km |
| 30 km/h (19 mph) | 6:09 /km (+69 s) | 4:39 /km (−21 s) | +24 s/km |
| 40 km/h (25 mph) | 6:48 /km (+108 s) | 4:20 /km (−40 s) | +34 s/km |
And for an 8:00/mile runner:
| Wind at running height | Headwind pace | Tailwind pace | Out-and-back average |
|---|---|---|---|
| 6 mph (10 km/h) | 8:23 /mi (+23 s) | 7:49 /mi (−11 s) | +6 s/mi |
| 9 mph (15 km/h) | 8:39 /mi (+39 s) | 7:48 /mi (−12 s) | +14 s/mi |
| 12 mph (19 km/h) | 8:58 /mi (+58 s) | 7:45 /mi (−15 s) | +22 s/mi |
| 19 mph (31 km/h) | 9:54 /mi (+114 s) | 7:25 /mi (−35 s) | +40 s/mi |
| 25 mph (40 km/h) | 10:54 /mi (+174 s) | 6:56 /mi (−64 s) | +55 s/mi |
All figures assume a 70 kg runner and wind measured at running height. A forecast wind is usually much stronger than what you feel, so read the next section before you panic about race day.
Why a tailwind never pays back a headwind
A tailwind helps, but far less than the same headwind hurts, typically by a factor of two to three. Two things cause this. First, because drag grows with the square of air speed, adding the wind to your speed raises the cost much more than subtracting it lowers it. Second, a light tailwind only cancels the breeze you create by running; once the wind matches your speed, you are running in still air, and only a stronger wind actually pushes you along.
Out-and-back courses always lose time. On a course that runs into the wind for half the distance and with it for the other half, you finish slower than on a calm day, even at a steady effort. The calculator shows this as the out-and-back average.
Forecast wind vs the wind you actually feel
Weather forecasts report wind at a standard height of 10 metres. Near the ground, friction from the surface slows the air, so at chest height (about 1.5 m) the wind is noticeably weaker, and much weaker among buildings and trees. Meteorologists describe this with the wind profile power law:
| Where you run | α (typical) | Share of the forecast wind you feel |
|---|---|---|
| Beach or waterfront | 0.11 | about 81 % |
| Open roads and fields | 0.16 | about 74 % |
| Parks with scattered buildings | 0.20 | about 68 % |
| Suburbs and towns | 0.30 | about 57 % |
| City centre with tall buildings | 0.40 | about 47 % |
Choose the matching option in the calculator and it converts the forecast for you. Gusts, tall buildings and gaps between them can still create local spots that are much windier.
How the calculator works
It keeps your metabolic effort the same as in still air and finds the pace that costs the same energy in the wind:
- Drag force: F = ½ × ρ × CdA × (running speed + headwind)², with air density ρ = 1.225 kg/m³ and drag area CdA = 0.8 × 0.266 × body surface area (Pugh, 1970). Body surface area is estimated from body weight (Livingston & Lee).
- Extra cost: each 1 % of body weight of horizontal resisting force raises the energy cost of running by about 6.13 % (da Silva and colleagues, 2022).
- Equal effort: the calculator solves for the speed at which running in the wind costs the same as your still-air pace. Crosswinds count only their head- or tail-on component.
This approach is the one described by John Davis at Running Writings, and it agrees closely with Pugh’s wind-tunnel measurements on a runner up to about 15–20 mph of headwind. The tailwind side assumes that an assisting force saves energy in the same proportion, which is less well tested, especially for strong tailwinds.
Running smart in the wind
Run by effort
Into the wind, hold effort or heart rate rather than pace. Chasing pace into a headwind burns energy you will not get back with the wind behind you.
Tuck in
Running close behind another runner shelters you from most of the air resistance (Pugh, 1971). Share the work in a group on windy stretches.
Bank nothing
Do not try to make up headwind losses by surging with the tailwind. Even effort over the whole course is fastest.
Adjust the goal
On a windy race day, set your goal from the out-and-back figure or the course layout, not your calm-day pace.
Combine with the heat pace calculator for warm days and the altitude pace calculator for races at elevation, then build splits with the pace calculator.
- Pugh LGCE (1970). Oxygen intake in track and treadmill running with observations on the effect of air resistance. J Physiol 207:823–835.
- Pugh LGCE (1971). The influence of wind resistance in running and walking and the mechanical efficiency of work against horizontal or vertical forces. J Physiol 213:255–276.
- Davies CTM (1980). Effects of wind assistance and resistance on the forward motion of a runner. J Appl Physiol 48:702–709.
- Davis J (2024). Calculating the effect of headwinds and tailwinds on running pacing and performance. Running Writings.
Last reviewed: September 2026 · Health disclaimer