Wind Chill and Frostbite Time Calculator
Calculate wind chill and approximate exposed-skin frostbite bands. Explore how temperature and wind change winter cold risk with an animated chart.
This wind chill calculator combines the measured air temperature and reported wind speed to estimate how cold exposed skin feels. It also reports an approximate frostbite time band from Environment and Climate Change Canada (ECCC). Engineers, students, outdoor workers and winter travellers can use it to compare weather conditions and understand the effect of wind on heat loss.
Enter one air temperature and the sustained wind speed reported at the standard weather-station height of 10 metres. Use the metric/US switch to enter Celsius or Fahrenheit and kilometres per hour or miles per hour. The same temperature field converts between scales. The defaults, −20 °C and 30 km/h, give a feels like temperature near −33 °C and ECCC's high-risk, 10–30 minute band. The extra-cooling result is a temperature difference, so it uses kelvin.
The calculation follows the joint NWS/MSC 2001 index in its Celsius form. Below 5 km/h and at or below freezing, it uses ECCC's separate light-wind equation. At zero wind that branch returns the air temperature. Above freezing in light wind, the displayed value is the air temperature and a note identifies that fallback. The index represents equivalent cooling; it does not predict a person's skin or core temperature.
Press play beside Wind sweep time to move a marker through winds from calm to 80 km/h while keeping your air temperature fixed. The ring marks your entered weather; the moving dot explores alternatives. The animation's seconds are display time, not minutes of skin exposure. Chart axes show both unit systems.
Frostbite guidance uses the calculated wind chill rounded to the nearest whole Celsius degree. The coloured bands show ECCC's published ranges. For milder conditions the chart supplies no short-time estimate; that does not establish a safe duration. The NWS comparison table shows why matching wind chill values can have different frostbite times at different wind speeds. This tool uses ECCC's broad ranges rather than interpolating an exact freezing time from NWS shading.
Health caveat: these ranges concern exposed skin and are not a personal safety limit, medical assessment or work/rest schedule. Wetness, clothing, circulation, age, health and local shelter change the outcome; strong winds can shorten the indicated times. Protect skin, stay dry and seek shelter early. Numbness or pale skin warrants prompt attention. Hypothermia can occur even when the calculator indicates no short-time frostbite band.
Wind accelerates cooling of pipes and equipment but does not lower them below the actual air temperature. This tool covers cold air from −50 to +10 °C and winds from 0 to 80 km/h; it does not model wet clothing, contact freezing, immersion, solar warming or protective equipment. See the linked method sources below for the published equations and guidance.
How it is calculated
The joint NWS/MSC 2001 wind chill index, described by Osczevski and Bluestein (2005), is evaluated in Celsius with the numerical wind speed in km/h:
The wind-speed input is a standard 10 m weather observation; do not apply an additional face-height correction. The empirical coefficients already embody the index's wind-height convention.
For and °C, use the ECCC glossary's light-wind equation:
At zero wind this equals . Above freezing with winds below 5 km/h, show air temperature as a labelled fallback. Small differences between the published Celsius and Fahrenheit coefficients, and tiny discontinuities at 5 km/h, arise from rounded empirical coefficients.
Frostbite times: classify the index rounded to the nearest whole Celsius degree using Environment Canada's factsheet p. 5: −28…−39 gives 10–30 min; −40…−47 gives 5–10 min; −48…−54 gives 2–5 min; ≤−55 gives less than 2 min. Warmer bands supply no short-time estimate. If air temperature is ≥0 °C, suppress a freezing-time band. The half-degree boundaries in the plot implement this rounding convention; the curve itself is unrounded.
The NWS comparison table reproduces only three published examples, without interpolation: the 0 °F / 15 mph example from NWS, and the two −58 °F examples from NOAA JetStream. NWS frostbite shading depends on air temperature and wind separately. The ECCC time output is not an exact lookup of NWS shading. No continuous frostbite-time equation or skin-temperature simulation is inferred from either chart.
Play time maps linearly to comparison winds of 0–80 km/h in 16 s. Static wind curves do not read the playing input. The main weather results depend only on the entered temperature and wind.
Assumptions
An exposed adult face, dry cold-air conditions, sustained wind and no direct solar warming. Clothing insulation, wetness, individual circulation, activity, terrain shelter and medical susceptibility are not parameterized. Conditions are held constant when reading a published band. ECCC category codes are an internal ordering, not a medical probability. Frostbite bands are approximate population guidance, never a safe exposure allowance.
Where it applies
Air temperature −50 to +10 °C (−58 to +50 °F); wind 0–80 km/h (0–49.7 mph). The standard branch starts at 5 km/h; above-zero calculations follow the NWS cold-weather domain, although ECCC forecasts publish wind chill only at or below zero. Below 5 km/h, use ECCC's extension only at or below zero; otherwise use the explicitly labelled air-temperature fallback.
ECCC warns that sustained winds above 50 km/h can cause faster frostbite. Calm conditions can still produce cold injury. No indicated short-time band means no minutes are supplied, not absence of risk. Wind chill does not make inanimate objects colder than the actual air temperature, and is not a heat-transfer coefficient for equipment design.
Health caveat: protect exposed skin and seek shelter before symptoms develop. For numbness, whitening or suspected cold injury, seek prompt medical help. The calculator does not diagnose frostbite, predict hypothermia, or establish occupational exposure limits. Current local weather alerts and individual needs take precedence.
References
- National Weather Service. Understanding Wind Chill: 2001 formula, domain, wind-height convention and 0 °F / 15 mph worked example. https://www.weather.gov/safety/cold-wind-chill-chart
- Environment Canada. Wind Chill Factsheet (2014), p. 5 exposure-risk bands and high-wind caveat; p. 6 numerical chart. https://www.canada.ca/content/dam/eccc/migration/main/meteo-weather/80b0f2af-9697-4bee-ab17-d401ebba5b4b/windchill_factsheet_en.pdf
- Environment and Climate Change Canada. Glossary, Wind Chill: standard and low-wind equations. https://climate.weather.gc.ca/glossary_e.html
- NOAA JetStream. Wind Chill: wind-dependent frostbite comparison examples. https://www.noaa.gov/jetstream/synoptic/wind-chill
- Osczevski, R. and Bluestein, M. (2005). The New Wind Chill Equivalent Temperature Chart. BAMS 86(10), 1453–1458. DOI: 10.1175/BAMS-86-10-1453. https://doi.org/10.1175/BAMS-86-10-1453
- ECCC. Wind chill and the Wind Chill Index, current public guidance checked 25 October 2026. https://www.canada.ca/en/services/environment/weather/severeweather/wind-chill-index.html
Inputs
| Input | Symbol | Unit | Default |
|---|---|---|---|
| Air temperature Enter the measured air temperature, not a forecast feels-like value. The unit switch converts this same input to °F. | T_air | °C | -20 |
| Wind speed at 10 m Use the reported sustained weather-station wind speed at 10 m (33 ft), not a face-level measurement. The unit switch offers mph. | V_wind | km/h | 30 |
| ▶ Wind sweep time Play to explore 0–80 km/h over 16 seconds at the entered air temperature. This is an animated comparison, not elapsed skin exposure; it does not change the entered-weather results. | t_scan | s | 6 |
Results
With the default inputs above, the calc gives:
| Result | Value |
|---|---|
| Feels-like temperature | -32.6 °C |
| Exposed skin: ECCC frostbite band | 10–30 min |
| ECCC exposure risk | High |
| Extra perceived cooling | 12.6 K |
Checked against sources
Each case below was calculated by this calc and agrees with the value from its source (within the tolerance where one is shown).
ECCC: −15 °C, 20 km/h → −24
Source: Environment Canada wind chill factsheet, p. 6: row 20 km/h, column −15 °C gives −24. Rounded chart precision ±0.51 K; p. 5 places −24 in moderate risk.
Inputs: Air temperature = -15 °C; Wind speed at 10 m = 20 km/h; the others as above.
| Result | Source | This calc |
|---|---|---|
| Feels-like temperature | -24 ± 0.51 °C | -24.17 °C |
| ECCC exposure-risk category | 1 | 1 |
ECCC: −20 °C, 30 km/h → −33
Source: Environment Canada factsheet p. 6, row 30 km/h and column −20 °C: −33. Page 5 gives 10–30 minutes at this wind chill. Chart values are rounded, not exact.
Inputs: the default inputs above.
| Result | Source | This calc |
|---|---|---|
| Feels-like temperature | -33 ± 0.51 °C | -32.568 °C |
| ECCC exposure-risk category | 2 | 2 |
ECCC: −30 °C, 40 km/h → −48
Source: Environment Canada factsheet p. 6, 40 km/h at −30 °C: −48. Page 5 severe band gives 2–5 minutes. Risk classification uses nearest whole Celsius degree.
Inputs: Air temperature = -30 °C; Wind speed at 10 m = 40 km/h; the others as above.
| Result | Source | This calc |
|---|---|---|
| Feels-like temperature | -48 ± 0.51 °C | -47.504 °C |
| ECCC exposure-risk category | 4 | 4 |
NWS: 0 °F and 15 mph → −19 °F
Source: NWS Understanding Wind Chill, https://www.weather.gov/safety/cold-wind-chill-chart : published 0 °F, 15 mph → −19 °F, exposed skin can freeze in 30 minutes. This checks the Celsius form against a separately published Fahrenheit example; published value is rounded.
Inputs: Air temperature = -17.778 °C; Wind speed at 10 m = 24.14 km/h; the others as above.
| Result | Source | This calc |
|---|---|---|
| Wind chill on the Fahrenheit scale | -19 ± 0.6 °F | -19.451 °F |
NOAA: −40 °F and 5 mph → −58 °F
Source: NOAA JetStream Wind Chill, https://www.noaa.gov/jetstream/synoptic/wind-chill : −40 °F and 5 mph gives −58 °F, with frostbite in 10 minutes or less. The NWS US and Canadian rounded coefficient sets differ slightly.
Inputs: Air temperature = -40 °C; Wind speed at 10 m = 8.047 km/h; the others as above.
| Result | Source | This calc |
|---|---|---|
| Wind chill on the Fahrenheit scale | -58 ± 0.65 °F | -57.558 °F |
NOAA: −20 °F and 45 mph → −58 °F
Source: NOAA JetStream Wind Chill: −20 °F and 45 mph gives −58 °F, with frostbite in 5 minutes or less. A similar wind chill to the light-wind case has a different NWS freezing-time band; ECCC broad ranges are not an exact NWS chart lookup.
Inputs: Air temperature = -28.889 °C; Wind speed at 10 m = 72.42 km/h; the others as above.
| Result | Source | This calc |
|---|---|---|
| Wind chill on the Fahrenheit scale | -58 ± 0.65 °F | -58.219 °F |
ECCC: −35 °C, 10 km/h → −45
Source: Environment Canada factsheet p. 6, 10 km/h at −35 °C gives −45; p. 5 places it in the very-high 5–10 minute band. Expected values come from the published chart, rounded to whole degrees.
Inputs: Air temperature = -35 °C; Wind speed at 10 m = 10 km/h; the others as above.
| Result | Source | This calc |
|---|---|---|
| Feels-like temperature | -45 ± 0.51 °C | -45.126 °C |
| ECCC exposure-risk category | 3 | 3 |
ECCC: −40 °C, 40 km/h → −61
Source: Environment Canada factsheet p. 6, 40 km/h at −40 °C gives −61; p. 5 assigns the ≤−55 band less than 2 minutes. Expected values come from the chart, not recalculation.
Inputs: Air temperature = -40 °C; Wind speed at 10 m = 40 km/h; the others as above.
| Result | Source | This calc |
|---|---|---|
| Feels-like temperature | -61 ± 0.51 °C | -60.873 °C |
| ECCC exposure-risk category | 5 | 5 |
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