Wind Chill mechanism

Model scope

The exact ambiguity requiring review is the undefined “frostbite time estimate”: no table, formula, interpolation behavior, or output units are supplied. The wind-chill calculation itself is numerically valid only under the stated NWS °F/mph constraints. Until the frostbite output is removed or fully specified and the Environment Canada attribution is corrected, the instrument should not be marked PASS.

• The numerical formula is the standard NWS wind-chill formula when T is in °F and V is in mph, but calling it jointly an “NWS/Environment Canada formula” is inaccurate: Environment Canada uses a different formula with temperature in °C and wind speed in km/h.
• The specification claims a frostbite-time estimate, but provides no frostbite-time formula, reference table, interpolation rule, or expected output definition.
• Wind chill is an index estimating perceived cold under specified assumptions, not a measured or universally applicable human body temperature.

Units and conventions

• T must be air temperature in degrees Fahrenheit.
• V must be wind speed in miles per hour; wind speed in km/h must be converted before applying this formula: mph = km/h × 0.621371.
• The stated NWS validity range is T ≤ 50 °F and V ≥ 3 mph.
• Wind speed must be nonnegative for the fractional power V^0.16, although the valid operational range requires V ≥ 3 mph.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "air_temperature_F": 30,
    "wind_speed_mph": 10
  },
  "expected_outputs": {
    "wind_chill_F": 21.25
  },
  "working": "V^0.16 = 10^0.16 = 1.44543977. 35.74 + 0.6215×30 = 35.74 + 18.645 = 54.385. -35.75×1.44543977 = -51.67447180. 0.4275×30×1.44543977 = 12.825×1.44543977 = 18.53776506. WC = 54.385 - 51.67447180 + 18.53776506 = 21.24829326 °F, which rounds to 21.25 °F."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The instrument needs explicit rejection for negative wind speeds because the plain-JavaScript power operation returns NaN. It also needs boundary enforcement and clear temperature-unit handling; otherwise out-of-range or ambiguously interpreted inputs can produce misleading results.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json