Source: https://guthlabs.ai/docs/instruments/wind-chill/mechanism/

instrument mechanism / verified-clean

# Wind Chill mechanism

The inspectable method record for Wind Chill, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## 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

[01**Overview**](<https://guthlabs.ai/docs/instruments/wind-chill/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/wind-chill/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/wind-chill/qualification/>)

## 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`