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Heat Index Calculator

"Feels like" temperature in hot and humid weather.

Compute the heat index — the apparent temperature combining air temperature and relative humidity — using the NWS Rothfusz regression.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

Inputs

°C
%

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

NWS Rothfusz regression on T (°F) and RH (%). The result is converted back to Celsius for display.

In depth

Compute the heat index — the apparent temperature combining air temperature and relative humidity — using the NWS Rothfusz regression.