{
  "schemaVersion": 1,
  "slug": "wind-chill-factor-calculator",
  "category": "weather",
  "kind": "implementation",
  "independentValidation": false,
  "implementationHash": "86e2bb459855078cc502ae156e8f07da8a4fb0aa46e398b64f09fdbdd819c246",
  "provenance": "Generated from the calculation contract used by the published page. Publication is not external validation.",
  "sourceFiles": [
    "data/calculators/wind-chill-factor-calculator.json",
    "src/engine.js"
  ],
  "runtimeSource": "/sources/engine.txt",
  "runtimeHash": "5c888d8898afbdee36267bb9977829e1e2ac568f6677c8ee87469c139864645c",
  "scope": "The compute function records implemented equations, constants, lookup tables and custom rules. Inputs record defaults and allowed values; outputs record precision and units. Defaults are examples, not recommendations. General background references are not evidence for this specific algorithm.",
  "publishedFormula": {
    "formula": "W = 13.12 + 0.6215T − 11.37V^0.16 + 0.3965TV^0.16",
    "vars": [
      [
        "T",
        "Air temperature (°C)"
      ],
      [
        "V",
        "Wind speed (km/h)"
      ],
      [
        "W",
        "Wind chill (°C)"
      ]
    ],
    "note": "Environment and Climate Change Canada equation with T in °C and V in km/h; applied here at T≤0°C and V≥5km/h, matching ECCC reporting conditions. This is not a personal frostbite-time forecast. [ECCC equation and conditions](https://climate.meteo.gc.ca/glossary_e.html)."
  },
  "externalEvidence": {
    "reviewedAt": "2026-10-04",
    "sources": [
      {
        "name": "U.S. National Weather Service — Understanding wind chill",
        "url": "https://www.weather.gov/safety/cold-wind-chill-chart"
      }
    ],
    "basis": "Uses the Celsius/km/h wind-chill relationship with coefficients 13.12, 0.6215, −11.37 and 0.3965, and wind speed raised to 0.16.",
    "limitations": "This page restricts the calculation to temperatures at or below 0°C and wind speeds of at least 5 km/h, a narrower temperature range than the NWS chart. It estimates perceived cold, not an object temperature.",
    "implementationHash": "86e2bb459855078cc502ae156e8f07da8a4fb0aa46e398b64f09fdbdd819c246"
  },
  "contract": {
    "compute": "const T=unit==='f'?(temperature-32)*5/9:temperature;const V=windSpeed;if(T>0||V<5)return{windChillC:null,windChillF:null,__error:'inputError'};const wc=13.12+0.6215*T-11.37*Math.pow(V,0.16)+0.3965*T*Math.pow(V,0.16);return{windChillC:wc,windChillF:wc*9/5+32};",
    "inputs": [
      {
        "name": "temperature",
        "type": "number",
        "default": -5,
        "min": -60,
        "max": 20,
        "step": 0.1,
        "slider": true
      },
      {
        "name": "windSpeed",
        "type": "number",
        "default": 25,
        "min": 0,
        "max": 300,
        "step": 0.5,
        "slider": true
      },
      {
        "name": "unit",
        "type": "select",
        "default": "c",
        "options": [
          {
            "value": "c"
          },
          {
            "value": "f"
          }
        ]
      }
    ],
    "outputs": [
      {
        "name": "windChillC",
        "precision": 1,
        "unit": "°C"
      },
      {
        "name": "windChillF",
        "precision": 1,
        "unit": "°F"
      }
    ],
    "interpret": null
  }
}