Heat Index Calculator
The heat-index equation combines temperature and relative humidity to estimate how hot conditions feel.
This calculator is free to use. Enable JavaScript to enter your values and see a result instantly.
How it works
The heat-index equation combines temperature and relative humidity to estimate how hot conditions feel.
Worked example
At 90°F and 60% humidity, the heat index is near 100°F.
Keep in mind
The formula is intended for warm conditions and shade.