{
  "slug": "wind-chill-calculator",
  "title": "Wind Chill Calculator",
  "heading": "Wind Chill Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/wind-chill-calculator",
  "summary": "Feels-like cold temperature from air temp and wind speed using the NWS 2001 formula.",
  "description": "Wind chill measures how fast exposed skin loses heat to moving air, which is why 20°F with a 30 mph wind feels far colder than 20°F dead calm. The NWS and Environment Canada adopted a joint formula in 2001 based on skin heat-transfer research using actual human subjects in a wind chamber, replacing an older and less accurate formula from the 1940s. It only applies meaningfully below 50°F with wind above 3 mph; outside that range wind has little cooling effect worth correcting for. The formula is used to issue wind chill advisories and warnings, and it directly informs frostbite time-to-injury charts — at -20°F wind chill, exposed skin can develop frostbite in under 30 minutes.",
  "formula": "WC = 35.74 + 0.6215×T − 35.75×V^0.16 + 0.4275×T×V^0.16, where T is °F and V is wind speed in mph.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=wind-chill-calculator",
  "inputs": [
    {
      "id": "temp",
      "label": "Air temperature",
      "kind": "number",
      "hint": null,
      "default": 20,
      "unit": "°F",
      "min": -50,
      "max": 50
    },
    {
      "id": "wind",
      "label": "Wind speed",
      "kind": "number",
      "hint": null,
      "default": 20,
      "unit": "mph",
      "min": 3,
      "max": 80
    }
  ],
  "outputs": [
    {
      "id": "WC",
      "label": "Wind chill (feels like)",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "diff",
      "label": "Degrees colder than air temp",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "frostbiteMin",
      "label": "Est. minutes to frostbite (-1 = low risk)",
      "format": "number",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Air temperature: 20 °F",
      "Wind speed: 20 mph"
    ],
    "outputs": [
      "Wind chill (feels like): 4",
      "Degrees colder than air temp: 16",
      "Est. minutes to frostbite (-1 = low risk): -1"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter air temperature (°F).",
      "Enter wind speed (mph).",
      "Read your wind chill (feels like) on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "temp": 12,
        "wind": 12
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "temp": 20,
        "wind": 20
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "temp": 32,
        "wind": 32
      }
    }
  ],
  "limitations": [
    "Estimates assume standard, average conditions — local rules, pricing, and materials vary.",
    "Results are rounded for readability; add a buffer before ordering, booking, or committing.",
    "Double-check anything with a real cost attached against a local quote."
  ],
  "faq": [
    {
      "q": "Why doesn't wind chill apply above 50°F?",
      "a": "The heat-transfer effect wind has on skin becomes negligible at warmer temperatures because your body isn't fighting to retain heat in the first place, so the NWS formula is only calibrated and reported for temperatures at or below 50°F with wind above 3 mph."
    },
    {
      "q": "Does wind chill affect car radiators or pipes the same way it affects skin?",
      "a": "No — wind chill is a biological metric based on human skin heat loss, not a physical temperature. Inanimate objects like car engines or water pipes cool toward the actual air temperature, not the wind chill value, though wind does speed up how fast they get there."
    },
    {
      "q": "How was the 2001 formula different from the old one?",
      "a": "The pre-2001 formula, from 1945, was based on how fast water froze in a plastic cylinder in Antarctica. The new formula uses a real skin heat-transfer model validated with human trials at a controlled wind chamber, producing milder (less extreme) values, especially at high wind speeds."
    },
    {
      "q": "What wind speed matters most?",
      "a": "Most of the cooling effect from wind happens by about 20-25 mph; beyond that the formula's V^0.16 term flattens out, so a jump from 30 to 50 mph adds far less additional chill than the jump from 5 to 20 mph."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/heat-index-calculator",
    "https://www.revenuelab.fyi/toolbox/dew-point-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Wind Chill Calculator (https://www.revenuelab.fyi/toolbox/wind-chill-calculator)"
}