Heat Index Calculator (NWS Rothfusz)

Get the felt-air temperature from heat and humidity.

Air temperature (°F)Relative humidity (%)

Result

Heat index

113.1 °F

Risk band

Danger

Uses the National Weather Service Rothfusz regression when temp ≥ 80°F and humidity ≥ 40%.

Band: Danger.

Heat-related illness is likely with prolonged exposure. Limit outdoor activity and stay hydrated.

About this tool

Type air temperature and relative humidity (or dew point) to get the National Weather Service Rothfusz Heat Index with the official warning bands. Targets the r/Heatwave, r/Fitness, and r/running 'is it safe to run outside' thread.

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