Wind chill on a bike: how cold it really feels at speed
Work out how cold your ride will feel at your speed and in the wind, then dress for it or decide to stay in.
The short answer
Wind chill on a bike comes from the air rushing past you: your riding speed plus any headwind, or minus a tailwind. At 0°C (32°F), riding at 20 km/h (12 mph) in still air feels like −6°C (21°F). At 30 km/h (19 mph) of air, it feels like −8°C (18°F).
Key takeaways
- On a bike, the air you feel is your speed plus any headwind, or minus a tailwind.
- At 0°C (32°F), riding at 20 km/h (12 mph) in still air feels like −6°C (21°F).
- The official index expects wind measured 10 m (33 ft) up, so multiply your air speed by 1.5 first.
- Frostbite needs air below freezing, but cold rain above freezing can still bring on hypothermia.
Definitions
- Wind chill
- How cold your skin feels when cold air and moving air combine, given as the calm-air temperature that would cool your face as fast.
- Air speed
- The speed of the air moving past your face, which on a bike is your riding speed plus a headwind or minus a tailwind.
- Wind at rider height
- The wind at about face height, roughly two-thirds of the forecast wind over open ground, and less in sheltered lanes.
What is wind chill on a bike?
Wind chill is how cold your skin feels when cold air and moving air combine. On a bike, most of that moving air is you: your speed, plus any headwind or minus a tailwind. It's the winter side of cycling in wind.
The US National Weather Service, Environment and Climate Change Canada (ECCC) and the Met Office use the same index, from the Joint Action Group for Temperature Indices (JAG/TI). The US and Canada adopted it in November 2001. It gives the calm-day temperature that would cool your bare face as fast.
Why does wind chill matter more on a bike?
Because you make your own wind. The index assumes a walker adds 4.8 km/h (3 mph) of air. A rider adds 20–40 km/h (12–25 mph), so a calm 0°C (32°F) morning feels like −6°C (21°F) at 20 km/h (12 mph).
You also sweat on climbs, then descend fast in damp kit. ECCC says wet skin loses heat much faster than dry skin, and that fingers, toes, ears and nose lose heat fastest.
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How cold does it feel at riding speed?
At 0°C (32°F), it feels like −6°C (21°F) at 20 km/h (12 mph) of air and −9°C (16°F) at 40 km/h (25 mph).
The index expects wind measured 10 m (33 ft) up, and assumes your face gets about two-thirds of it (Bluestein and Osczevski, 2002). On a bike, your air speed is already the air at your face, so multiply it by 1.5 first. Then use the chart or the formula: wind chill (°C) = 13.12 + 0.6215T − 11.37V^0.16 + 0.3965T·V^0.16, with T in °C and V in km/h. The US version uses °F and mph: 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16.
| Air temperature | 20 km/h (12 mph) of air | 30 km/h (19 mph) of air | 40 km/h (25 mph) of air |
|---|---|---|---|
| 10°C (50°F) | 7°C (45°F) | 6°C (43°F) | 5°C (41°F) |
| 5°C (41°F) | 0°C (32°F) | −1°C (30°F) | −2°C (28°F) |
| 0°C (32°F) | −6°C (21°F) | −8°C (18°F) | −9°C (16°F) |
| −5°C (23°F) | −13°C (9°F) | −15°C (5°F) | −16°C (3°F) |
| −10°C (14°F) | −20°C (−4°F) | −21°C (−6°F) | −23°C (−9°F) |
Putting your riding speed straight into the formula, a common shortcut, understates the chill by about 1–1.5°C (2–3°F).
What changes how cold you feel?
The wind against your road changes it most. At rider height, the wind is roughly two-thirds of the forecast over open ground, and less in sheltered lanes (why the wind on your bike isn't the forecast). Add it in a headwind, subtract it in a tailwind. A crosswind adds little.
| Ride (illustrative weather) | Air temperature | Air speed you feel | Feels like |
|---|---|---|---|
| London, December, 20 km/h (12 mph), calm | 3°C (37°F) | 20 km/h (12 mph) | −3°C (27°F) |
| Same ride into a 15 km/h (9 mph) forecast wind | 3°C (37°F) | 30 km/h (19 mph) | −4°C (25°F) |
| Toronto, January, 25 km/h (15.5 mph), same wind side-on | −5°C (23°F) | 27 km/h (17 mph) | −14°C (7°F) |
| Canberra, July, 30 km/h (19 mph), calm | −2°C (28°F) | 30 km/h (19 mph) | −10°C (14°F) |
| Alpine descent, 50 km/h (31 mph) | 5°C (41°F) | 50 km/h (31 mph) | −3°C (27°F) |
Descents are usually coldest: you stop pedalling as the air speed doubles. Sun works the other way: ECCC says bright sunshine can make you feel up to 10°C (18°F) warmer, and the index assumes none.
## What should you wear for each wind-chill band?Dress for the coldest stretch, usually the descent or the headwind home. Cycling UK advises layers: a synthetic or merino base, then warmers, a gilet or windproof soft shell. ECCC adds: stay dry, and open a layer if you sweat.
| Feels like at riding speed | What to wear |
|---|---|
| 5 to 10°C (41 to 50°F) | Long-sleeve base layer, arm and knee warmers or a gilet, light full-finger gloves |
| 0 to 5°C (32 to 41°F) | Thermal jersey, windproof jacket, tights, full-finger gloves, thermal cap, overshoes |
| −10 to 0°C (14 to 32°F) | Add insulated windproof gloves, a snood and winter overshoes or boots |
| Below −10°C (14°F) | Cover your face too; ECCC calls this moderate risk, with frostbite possible on long exposure |
How cold is too cold to cycle?
There's no official cycling limit, but four lines are worth respecting:
- A cold warning. If a National Weather Service or ECCC cold warning covers your route, stay in.
- A wind chill of −27. ECCC says frostbite risk rises rapidly below it, and skin can freeze in 10 to 30 minutes. At 25 km/h (15.5 mph) of air, that's about −15°C (5°F).
- Ice. At or below 0°C (32°F), wet roads can freeze.
- Cold rain. Rain that feels 5°C (41°F) or colder soaks you through. At 25 km/h (15.5 mph), that's air of about 9°C (48°F).
Discomfort comes sooner. At 25 km/h (15.5 mph), it feels like 0°C (32°F) once the air drops to about 5°C (41°F). If your hands are too numb to brake, head home.
How do you plan a cold ride around wind chill?
Check the night before and again in the morning:
- Read the temperature and wind for the hours you'll ride; see reading a weather forecast for a bike ride.
- Find the headwind stretches and descents, and work out your air speed there.
- Read the table and dress for the coldest stretch.
- Consider riding into the wind first, so you come home damp with the wind behind you.
A headwind costs time too: see how much a headwind slows you down. If it's windy as well, check how windy is too windy to cycle.
Frequently asked questions
Can you get frostbite cycling when it's above freezing?
No. The US National Weather Service says frostbite needs the actual air temperature near your skin to be below freezing, so wind chill alone can't freeze your skin on a 3°C (37°F) day. But wet kit and a long, fast descent above freezing can still bring on hypothermia, so carry a dry layer.
Does sunshine make a cold ride feel warmer?
Yes, noticeably. Environment and Climate Change Canada says bright sunshine can make you feel as much as 10°C (18°F) warmer, and the US National Weather Service says 10–18°F (about 6–10°C). The index assumes no sun at all, so on a bright morning the chart is the cautious figure.
Does a tailwind stop you feeling the cold?
It can, while it lasts. If the wind at rider height matches your speed, almost no air moves past you, so you feel the plain air temperature and may start to sweat. Turn into the wind and that air hits damp kit at full speed, so zip up before you turn.
Does wind chill affect your bike or e-bike battery?
Not the way it affects you. The US National Weather Service says wind chill applies only to people and animals: wind cools objects faster, but never below the air temperature. On a −5°C (23°F) day, your bike, bottles and battery reach −5°C (23°F) at most, whatever your speed.
Does humidity change wind chill on a bike?
Hardly. When the US National Weather Service tested the current index on 12 volunteers, humidity changed the result by less than one degree, so it was left out of the formula. Water on you matters far more: Environment and Climate Change Canada says wet skin loses heat much faster than dry skin, and wet clothing loses heat almost as fast as bare skin.
Get the wind for your ride.
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Make a free ride page →Sources and method
- US National Weather Service (2026). Understanding wind chill (wind chill chart, formula and FAQ)
- US National Weather Service, El Paso office (2026). Wind chill (calculation sheet)
- AMS 15th Conference on Biometeorology and Aerobiology (2002). The basis for the new wind chill temperature chart (Bluestein and Osczevski)
- Environment Canada (2014). Wind chill: the chilling facts
- Government of Canada (Environment and Climate Change Canada) (2025). Wind chill and the Wind Chill Index
- Met Office (2026). Wind chill factor
- Cycling UK (2026). What cycle clothing to wear when it's cold (Matt Lamy)
Wind chill values use the JAG/TI wind chill index in its metric form, as printed by Bluestein and Osczevski (2002): wind chill (°C) = 13.12 + 0.6215T − 11.37V^0.16 + 0.3965T·V^0.16, with T the air temperature in °C and V the wind in km/h at 10 m. The index assumes the wind at face height is two-thirds of the 10 m wind (open field), so we enter a rider's air speed at the face multiplied by 1.5: 20, 30 and 40 km/h of air are read as 30, 45 and 60 km/h, and every value in the main table matches the published metric chart (Bluestein and Osczevski, Table 2) at those wind speeds once rounded. Air speed is riding speed plus the wind at rider height along the road (minus it for a tailwind); for a crosswind the two are combined at right angles (25 and 10 km/h give about 27 km/h). Wind at rider height is taken as two-thirds of the forecast 10 m wind, the same open-field ratio, so a 15 km/h forecast wind becomes 10 km/h. The index also builds in a walking speed of 4.8 km/h (3 mph); we don't subtract it, which makes our figures about 0.3–1.1°C colder than if we did, a cautious choice. Plugging riding speed straight into the formula (the common shortcut) gives −5, −6 and −7 at 0°C for 20, 30 and 40 km/h, against our −6, −8 and −9 (unrounded, 1.2–1.4°C warmer). The air temperatures at which a rider at 25 km/h (15.5 mph) of air reaches a given wind chill (0, −6, 5 and −27) were solved from the same formula. Values are rounded to the nearest whole °C; °F values convert the rounded °C figure (°F = °C × 1.8 + 32), and speeds use 1 mile = 1.609 km. The index is defined at 10°C (50°F) and below. Ride examples are illustrative weather, not observations. Clothing bands are our editorial guidance, using Environment and Climate Change Canada's risk bands and advice and Cycling UK's clothing advice; they are not medical advice.
About the author
Wes Thomson, Founder, Windline. Wes Thomson builds Windline, live wind and weather forecasts timed to when riders reach each stretch of road. He built it for his own 2,093 km tour from Pont Drift to Cape Town, and writes these guides with the same focus: what the wind will do to your ride, and how to plan around it.