What is this calculator?
Estimate apparent temperature from heat and humidity using the NWS method.
What can you use it for?
Use it for practical planning, conversions, measurement or checking the result described here. Estimate apparent temperature from heat and humidity using the NWS method.
How to use it
- Enter air temperature (°f).
- Enter relative humidity (%).
- Select Calculate (or Generate for random tools).
- Read the answer and any additional results below the form. Check the units and the limits of the method.
Formula and method
The temperature-humidity regression includes the NWS low-humidity and high-humidity adjustments. The assumptions are shade and light wind.
Worked example
Air temperature (°F): 90, Relative humidity (%): 60. The result is 99.6777179 °F (heat index).
Assumptions and limits
Shaded, light-wind estimate. Sun exposure and individual vulnerability are not modelled.
Method references
Frequently asked questions
What inputs does the Heat Index Calculator need?
Use air temperature (°f), relative humidity (%). Read the answer and any additional results below the form. Check the units and the limits of the method.
What assumptions apply to the Heat Index Calculator?
Shaded, light-wind estimate. Sun exposure and individual vulnerability are not modelled.