Calculator Tools
Wind Chill Calculator
Calculate wind chill and frostbite risk using the official 2001 NWS index. Fahrenheit, Celsius, mph, km/h, m/s, and knots, all in your browser.
Temperature units
Wind units
Wind speed should be the 10 m anemometer reading; that is the value most weather forecasts report.
Wind chill
6.2 °F
Equivalent to -14.3 °C
Low risk
Frostbite is unlikely in normal cold-weather exposure. Dress in layers and keep skin covered when outdoors for extended periods.
- Air temperature
- 20.0 °F
- Wind speed
- 15.0 mph
- Drop below air temperature
- 13.8 °F
- Frostbite risk band
- Low risk
-6.7 °C
15.0 mph / 24.1 km/h / 6.7 m/s
How much colder it feels than the still-air temperature.
Outside frostbite warning bands
NWS wind chill reference
Read a cell to see the wind chill for a given air temperature row and wind speed column. Colours match the frostbite risk bands above.
Values shown in Fahrenheit.
| Air temp | 5 mph | 10 mph | 15 mph | 20 mph | 25 mph | 30 mph | 35 mph | 40 mph | 45 mph | 50 mph |
|---|---|---|---|---|---|---|---|---|---|---|
| 40 °F | 36 | 34 | 32 | 30 | 29 | 28 | 28 | 27 | 26 | 26 |
| 30 °F | 25 | 21 | 19 | 17 | 16 | 15 | 14 | 13 | 12 | 12 |
| 20 °F | 13 | 9 | 6 | 4 | 3 | 1 | 0 | -1 | -2 | -3 |
| 10 °F | 1 | -4 | -7 | -9 | -11 | -12 | -14 | -15 | -16 | -17 |
| 0 °F | -11 | -16 | -19 | -22 | -24 | -26 | -27 | -29 | -30 | -31 |
| -10 °F | -22 | -28 | -32 | -35 | -37 | -39 | -41 | -43 | -44 | -45 |
| -20 °F | -34 | -41 | -45 | -48 | -51 | -53 | -55 | -57 | -58 | -60 |
| -30 °F | -46 | -53 | -58 | -61 | -64 | -67 | -69 | -71 | -72 | -74 |
| -40 °F | -57 | -66 | -71 | -74 | -78 | -80 | -82 | -84 | -86 | -88 |
- Low risk
- Moderate risk
- High risk
- Severe risk
- Extreme risk
What this tool covers
- 2001 NWS index: uses the Osczevski and Bluestein revision adopted by the U.S. National Weather Service and Environment Canada. The same equation backs every official cold-weather feels-like report on North American forecasts.
- Frostbite warnings: the chart bands match the NWS public chart: about 30 minutes, 10 minutes, 5 minutes, and under 2 minutes on exposed skin. The band is highlighted next to the result.
- Both unit systems: type Fahrenheit or Celsius, mph, km/h, m/s, or knots. Every flip keeps the underlying physical conditions the same.
- Honest cutoffs: when the air is above 50 F (10 C) or the wind is at or below 3 mph (5 km/h), the chart does not publish a wind-chill value. The tool says so instead of pretending the equation still applies.
- Reference chart: renders the NWS-style table of wind chill across common temperature rows and wind columns, colour-coded by frostbite band, so you can sanity check the regression at a glance.
- Local only: nothing you type is uploaded. All math runs in the browser.
How to use
- Pick Fahrenheit or Celsius, then enter the current air temperature.
- Pick mph, km/h, m/s, or knots, then enter the wind speed at the standard 10 m anemometer height.
- Read the wind chill, the drop below the air temperature, and the NWS frostbite risk band; use the Copy report button to copy the summary.
- Tap a quick wind preset to try common values; scroll down to the reference chart to scan wind chill across the full temperature and wind grid.
About this tool
Wind Chill Calculator reports the cold-weather feels-like temperature using the 2001 National Weather Service and Environment Canada Wind Chill Temperature Index, the same equation behind every official cold-weather advisory in North America. Enter an air temperature in Fahrenheit or Celsius and a wind speed in mph, km/h, m/s, or knots; the tool returns the wind chill in both temperature units, the drop below the still-air temperature, and the NWS frostbite risk band (about 30 minutes, 10 minutes, 5 minutes, or under 2 minutes on exposed skin). The cutoffs are honest: above 50 F (10 C) or at or below 3 mph (5 km/h) the chart does not publish a value, so the tool says no wind-chill effect instead of pretending the regression still applies. A built-in NWS-style reference chart spans 40 F down to -40 F and 5 mph to 50 mph, colour-coded by frostbite risk, for sanity checks and planning. Useful for dressing children for the school bus on a sub-zero morning, scheduling cold-weather outdoor work, deciding whether to delay a run or a hike, briefing volunteers before a winter event, and answering questions like what is -10 F at 25 mph or how cold does 5 m/s feel at 0 C. Pair it with the heat-index calculator for warm-weather feels-like values; together they cover the full apparent-temperature range. Every conversion and risk classification runs locally in your browser; the values you type are never uploaded to a server.
Free to use. Works in your browser. No signup, no login.
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