🌡️ Heat Index Calculator

📘 How This Calculator Works

The heat index estimates the "feels like" temperature by combining air temperature and relative humidity.

This calculator uses the NOAA formula for heat index valid for temperatures > 80°F and humidity > 40%:

HI = -42.379 + 2.04901523*T + 10.14333127*RH 
     - 0.22475541*T*RH - 0.00683783*T² - 0.05481717*RH² 
     + 0.00122874*T²*RH + 0.00085282*T*RH² - 0.00000199*T²*RH²

Where T = temperature (°F), RH = relative humidity (%).

🤖 Ask Goatic AI – FAQ

What if temperature is below 80°F?

Heat index calculation is less accurate below 80°F; actual temperature is more relevant.

Can this be used with Celsius?

This version requires °F. You can convert Celsius to Fahrenheit first.

Why is humidity important?

Humidity affects how hot it feels because it impacts sweat evaporation.