{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"wind-chill"},"result":{"entity_type":"calculator","id":"wind-chill","calculator_id":"wind-chill","canonical_url":"https://tttkmbb.com/weather/wind-chill","name":"Wind Chill Calculator","title":"Wind Chill Calculator – Feels-Like Temperature from Air Temperature and Wind Speed (NWS/Environment Canada 2001 Formula)","category":"weather","category_name":"Weather & Environment","tool_name":"calculate_wind_chill","featured_mcp_tool":false,"description":"Computes the wind chill temperature from air temperature and wind speed with the 2001 JAG/TI formula used by the US National Weather Service and Environment Canada, and reports the frostbite risk band for exposed skin.","use_when":"You need the 'feels like' temperature in cold windy weather, or how quickly exposed skin can freeze, for temperatures at or below 10 °C (50 °F) and winds of at least 4.8 km/h (3 mph).","do_not_use_when":"The temperature is above 10 °C (50 °F) or the wind is below 4.8 km/h (the formula is undefined there); for hot humid weather use heat-index.","inputs":[{"name":"temperature","label":"Air temperature","type":"number","required":true,"min":-100,"max":60,"description":"Air temperature in temperature_unit; must be at or below 10 °C (50 °F).","example":-10},{"name":"temperature_unit","label":"Temperature unit","type":"enum","required":false,"default":"c","values":[{"value":"c","label":"Celsius (°C)","aliases":["celsius","°c","degc"]},{"value":"f","label":"Fahrenheit (°F)","aliases":["fahrenheit","°f","degf"]}],"description":"Unit of the temperature input(s).","example":"c"},{"name":"wind_speed","label":"Wind speed","type":"number","required":true,"min":0,"max":400,"description":"Wind speed measured at 10 m (standard anemometer height), in wind_speed_unit; must be at least 4.8 km/h (3 mph).","example":30},{"name":"wind_speed_unit","label":"Wind speed unit","type":"enum","required":false,"default":"kmh","values":[{"value":"kmh","label":"km/h","aliases":["km/h","kph","kilometres per hour","kilometers per hour"]},{"value":"mph","label":"mph","aliases":["miles per hour","mi/h"]},{"value":"ms","label":"m/s","aliases":["m/s","metres per second","meters per second"]},{"value":"knots","label":"knots","aliases":["kn","kt","kts","knot"]}],"description":"Unit of the wind speed input.","example":"kmh"}],"outputs":[{"name":"wind_chill_c","label":"Wind chill","type":"number","unit":"°C","decimals":1,"description":"Wind chill temperature in Celsius."},{"name":"wind_chill_f","label":"Wind chill","type":"number","unit":"°F","decimals":1,"description":"Wind chill temperature in Fahrenheit."},{"name":"temperature_c","label":"Air temperature","type":"number","unit":"°C","decimals":1,"description":"Input temperature in Celsius."},{"name":"wind_speed_kmh","label":"Wind speed","type":"number","unit":"km/h","decimals":1,"description":"Input wind speed in km/h."},{"name":"frostbite_risk","label":"Frostbite risk","type":"string","decimals":4,"description":"Environment Canada risk band for the wind chill value."},{"name":"frostbite_time","label":"Exposed skin can freeze in","type":"string","decimals":4,"description":"Freezing time for exposed skin from the Environment Canada table (bands start at −28 °C)."}],"input_schema":{"type":"object","properties":{"temperature":{"description":"Air temperature in temperature_unit; must be at or below 10 °C (50 °F).","type":"number","minimum":-100,"maximum":60,"examples":[-10]},"temperature_unit":{"description":"Unit of the temperature input(s).","type":"string","enum":["c","f"],"default":"c","examples":["c"]},"wind_speed":{"description":"Wind speed measured at 10 m (standard anemometer height), in wind_speed_unit; must be at least 4.8 km/h (3 mph).","type":"number","minimum":0,"maximum":400,"examples":[30]},"wind_speed_unit":{"description":"Unit of the wind speed input.","type":"string","enum":["kmh","mph","ms","knots"],"default":"kmh","examples":["kmh"]}},"additionalProperties":false,"required":["temperature","wind_speed"]},"output_schema":{"type":"object","properties":{"wind_chill_c":{"description":"Wind chill temperature in Celsius. Unit: °C.","type":"number","x-unit":"°C"},"wind_chill_f":{"description":"Wind chill temperature in Fahrenheit. Unit: °F.","type":"number","x-unit":"°F"},"temperature_c":{"description":"Input temperature in Celsius. Unit: °C.","type":"number","x-unit":"°C"},"wind_speed_kmh":{"description":"Input wind speed in km/h. Unit: km/h.","type":"number","x-unit":"km/h"},"frostbite_risk":{"description":"Environment Canada risk band for the wind chill value.","type":"string"},"frostbite_time":{"description":"Freezing time for exposed skin from the Environment Canada table (bands start at −28 °C).","type":"string"}}},"formula":"WC(°C) = 13.12 + 0.6215·T − 11.37·V^0.16 + 0.3965·T·V^0.16 with T in °C and V in km/h (identical to the NWS form WC(°F) = 35.74 + 0.6215·T − 35.75·V^0.16 + 0.4275·T·V^0.16 with T in °F, V in mph); defined for T ≤ 10 °C and V ≥ 4.8 km/h","method":"The 2001 Joint Action Group for Temperature Indices formula models heat loss from a bare face walking at 4.8 km/h into the wind, with wind measured at 10 m. Frostbite bands: −28 to −39 °C skin freezes in 10–30 min, −40 to −47 in 5–10 min, −48 to −54 in 2–5 min, −55 and colder in under 2 min.","sources":[{"name":"NWS – Wind Chill Chart (2001 JAG/TI formula)","url":"https://www.weather.gov/safety/cold-wind-chill-chart","type":"government","retrieved_at":"2026-09-24"},{"name":"Environment and Climate Change Canada – Wind chill and the Wind Chill Index (frostbite risk table)","url":"https://www.canada.ca/en/services/environment/weather/severeweather/wind-chill-index.html","type":"government","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"−10 °C, 30 km/h","inputs":{"temperature":-10,"temperature_unit":"c","wind_speed":30,"wind_speed_unit":"kmh"},"expected":{"wind_chill_c":-19.5,"wind_chill_f":-3.1,"wind_speed_kmh":30,"frostbite_risk":"Moderate risk (−10 to −27 °C)"},"url":"https://tttkmbb.com/api/v1/calculate/wind-chill?temperature=-10&temperature_unit=c&wind_speed=30&wind_speed_unit=kmh"},{"name":"5 °F, 25 mph","inputs":{"temperature":5,"temperature_unit":"f","wind_speed":25,"wind_speed_unit":"mph"},"expected":{"wind_chill_f":-17.5,"wind_chill_c":-27.5,"temperature_c":-15,"wind_speed_kmh":40.2},"url":"https://tttkmbb.com/api/v1/calculate/wind-chill?temperature=5&temperature_unit=f&wind_speed=25&wind_speed_unit=mph"}],"faq":[{"q":"Why is there no result for light winds or mild temperatures?","a":"The formula is only defined for air temperatures at or below 10 °C (50 °F) and winds of at least 4.8 km/h (3 mph); outside that range the calculator returns an error rather than a misleading number."},{"q":"Is the wind measured at face height?","a":"No. The formula expects the standard 10 m anemometer wind; it internally converts to face-level wind (about 2/3 of the 10 m value)."},{"q":"Does wind chill lower the temperature of objects?","a":"No. It expresses the rate of heat loss from skin; a car radiator or pipe never cools below the actual air temperature."}],"tags":["wind chill","feels like temperature","frostbite time","cold weather","wind chill formula"],"related":[{"calculator_id":"heat-index","reason":"The hot-weather counterpart."},{"calculator_id":"speed","reason":"Convert wind speeds between km/h, mph, m/s and knots."},{"calculator_id":"temperature","reason":"Plain °C ↔ °F conversion."}],"links":{"html":"https://tttkmbb.com/weather/wind-chill","markdown":"https://tttkmbb.com/weather/wind-chill.md","json":"https://tttkmbb.com/weather/wind-chill.json","api":"https://tttkmbb.com/api/v1/calculate/wind-chill","schema":"https://tttkmbb.com/api/v1/calculators/wind-chill","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:47:51Z"}