{
  "schemaVersion": 1,
  "slug": "wind-chill-calculator",
  "category": "weather",
  "kind": "implementation",
  "independentValidation": false,
  "implementationHash": "b569908dbb0dca95d0697f58b574d69ae973c581c63256c9a03b029757bfb20d",
  "provenance": "Generated from the calculation contract used by the published page. Publication is not external validation.",
  "sourceFiles": [
    "data/calculators/wind-chill-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 = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275TV^0.16",
    "vars": [
      [
        "T",
        "Air temperature (°F)"
      ],
      [
        "V",
        "Wind speed (mph)"
      ],
      [
        "W",
        "Wind chill (°F)"
      ]
    ],
    "note": "US equation with T in °F and V in mph; Celsius input is converted. Defined only for T≤50°F and V>3mph. This result is not a personal frostbite-time estimate. [NWS formula and limits](https://www.weather.gov/safety/cold-wind-chill-chart)."
  },
  "externalEvidence": {
    "reviewedAt": "2026-10-04",
    "sources": [
      {
        "name": "U.S. National Weather Service — Wind chill",
        "url": "https://www.weather.gov/epz/wxcalc_windchill"
      }
    ],
    "basis": "Uses the NWS Fahrenheit/mph wind-chill relationship with coefficients 35.74, 0.6215, −35.75 and 0.4275, and wind speed raised to 0.16.",
    "limitations": "Inputs above 50°F or at wind speeds of 3 mph or less are rejected. Estimates perceived cold on exposed skin, not an object temperature or an individualized injury timer.",
    "implementationHash": "b569908dbb0dca95d0697f58b574d69ae973c581c63256c9a03b029757bfb20d"
  },
  "contract": {
    "compute": "const T=unit==='c'?temperature*9/5+32:temperature;const V=windSpeed;if(T>50||V<=3)return{windChillF:null,windChillC:null,__error:'inputError'};const wc=35.74+0.6215*T-35.75*Math.pow(V,0.16)+0.4275*T*Math.pow(V,0.16);return{windChillF:wc,windChillC:(wc-32)*5/9};",
    "inputs": [
      {
        "name": "temperature",
        "type": "number",
        "default": 25,
        "min": -80,
        "max": 60,
        "step": 0.1,
        "slider": true
      },
      {
        "name": "windSpeed",
        "type": "number",
        "default": 15,
        "min": 0,
        "max": 200,
        "step": 0.5,
        "slider": true
      },
      {
        "name": "unit",
        "type": "select",
        "default": "f",
        "options": [
          {
            "value": "f"
          },
          {
            "value": "c"
          }
        ]
      }
    ],
    "outputs": [
      {
        "name": "windChillF",
        "precision": 1,
        "unit": "°F"
      },
      {
        "name": "windChillC",
        "precision": 1,
        "unit": "°C"
      }
    ],
    "interpret": null
  }
}