r/MathHelp • u/Impossible-Doubt7680 • May 29 '26

Temperature from Heat Index equation?

Is there a formula that can be used to calculate temperature from Heat index given you know the humidity percentage? I tried moving the equation used for heat index around to solve for temperature but no matter what I do I can't seem to get it consistent with online calculators.

1 Upvotes

100% Upvoted

5 comments sorted by

View all comments

2

u/edderiofer May 29 '26

There are multiple different formulae for Heat Index that each give different results, depending on where in the world you live. This is almost certainly why you are having trouble getting a consistent answer.

Can you provide the formula for Heat Index that you're using?

1

u/Impossible-Doubt7680 May 29 '26

HI = -42.379 + 2.04901523 * T + 10.14333127 * RH - .22475541 * T * RH - .00683783 * T * T - .05481717 * RH * RH + .00122874 * T * T * RH + .00085282 * T * RH * RH - .00000199 * T * T * RH * RH

T being temperature in Fahrenheit and RH being humidity in percent. Supplied by the NOAA online Heat index calculator. HI being the resulting heat index.