Wind chill estimates how cold the wind makes it feel on exposed skin. Heat index combines temperature and humidity to determine the human‑perceived equivalent temperature. Both are based on NOAA formulas.
Wind Chill (°F) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16).
Heat Index is derived from multiple regression analysis by Rothfusz, combining air temperature and relative humidity.
Typically when air temperature is ≤ 50°F (10°C) and wind speed ≥ 3 mph.
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