Heat Index (Apparent Temperature) implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t4-267

Effect

Computation or source lookup only

Input and validation requirements

An unchecked extreme input causes JavaScript floating-point overflow and a NaN heat index, so the instrument must reject out-of-domain magnitudes before evaluating the polynomial. The unit ambiguity also demonstrates that an omitted temperature unit can materially change the result.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "air_temperature_F": 90,
    "relative_humidity_percent": 60
  },
  "expected_outputs": {
    "heat_index_F": 99.6778,
    "heat_index_C": 37.5988,
    "risk_category": "Extreme Caution"
  },
  "working": "T=90, R=60, T²=8100, R²=3600, TR=5400, T²R=486000, TR²=324000, T²R²=29160000. HI_F = -42.379 + (2.04901523×90) + (10.14333127×60) - (0.22475541×5400) - (0.00683783×8100) - (0.05481717×3600) + (0.00122874×486000) + (0.00085282×324000) - (0.00000199×29160000) = -42.379 + 184.4113707 + 608.5998762 - 1213.679214 - 55.386423 - 197.341812 + 597.16764 + 276.31368 - 58.0284 = 99.6778179°F. HI_C=(99.6778179-32)×5/9=37.5987877°C. 99.6778°F is in the 90–102°F Extreme Caution band."
}

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