Heat Index Calculator

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If the temperature is 90° Fahrenheit and the relative humidity is 70%,

What is the Heat Index factor?

Heat Index (HI) Formula is denoted below:

HI = -42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 0.00683783T² - 0.05481717R² + 1.22874T²R + 0.00085282TR² - 0.00000199T²R²

Plug in values

HI = -42.379 + 2.04901523(90) + 10.14333127(0.7) - 0.22475541(90)(0.7) - 0.00683783(90)² - 0.05481717(0.7)² + 1.22874(90)²(0.7) + 0.00085282(90)(0.7)² - 0.00000199(90)²(0.7)²

HI = -42.379 + 184.4113707 + 7.30331889 - 14.15959083 - 55.386423 + 0.0268604133 + 54.187434 + 3.38484258

HI (°F) = 137.39

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What is the Answer?

HI (°F) = 137.39

How does the Heat Index Calculator work?

Free Heat Index Calculator - Given a temperature in Fahrenheit and a relative humidity percentage, this calculates the Heat Index.
This calculator has 2 inputs.

What 1 formula is used for the Heat Index Calculator?

HI = -42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 0.00683783T² - 0.05481717R² + 1.22874T²R + 0.00085282TR² - 0.00000199T2R²

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What 4 concepts are covered in the Heat Index Calculator?

fahrenheit: Unit of temperature
heat: energy that is transferred from one body to another as the result of a difference in temperature
heat index: measure of how hot it really feels when relative humidity is factored in with the actual air temperature
temperature: degree of hotness or coldness measured on a definite scale. An average measure of the kinetic energy for particles of matter.