Heat Index Chart - Relative Humidity vs. Air Temperature

As one who is severely discomforted by a combination of heat and humidity, this kind of table is of great interest. If I am going to be miserable, I want to know exactly how miserable I really am! This information is derived from NOAA Click here for a windchill chart.

Extreme Danger - Heat stroke or sun stroke likely

Danger - Sunstroke, muscle cramps and/or heat exhaustion likely

Extreme Caution - Sunstroke, muscle cramps and/or heat exhaustion possible

Caution - Fatigue possible

NOAA provides the following equation for calculating heat index:
       HI = -42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 6.83783x10^-3T²- 5.481717x10^-2R² + 1.22874x10^-3T²R + 8.5282x10^-4TR² - 1.99x10^-6T²R²,

           where T = ambient dry bulb temperature (°F) R = relative humidity (integer percentage)

      "Because this equation is obtained by multiple regression analysis, (HI) has an error of ±1.3°F"

Air Temp (°F)	Relative Humidity (%)
	40	45	50	55	60	65	70	75	80	85	90	95	100
110	136
108	130	137
106	124	130	137
104	119	124	131	137
102	114	119	124	130	137
100	109	114	118	124	129	136
98	105	109	113	117	123	128	134
96	101	104	108	112	116	121	126	132
94	97	100	102	106	110	114	119	124	129	136
92	94	96	99	101	105	108	112	116	121	126	131
90	91	93	95	97	100	103	106	109	113	117	122	127	132
88	88	89	91	93	95	98	100	103	106	110	113	117	121
86	85	87	88	89	91	93	95	97	100	102	105	108	112
84	83	84	85	86	88	89	90	92	94	96	98	100	103
82	81	82	83	84	84	85	86	88	89	90	91	93	95
80	80	80	81	81	82	82	83	84	84	85	86	86	87




About RF Cafe
Copyright: 1996 - 2024 Webmaster: Kirt Blattenberger, BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived... All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged. My Hobby Website: AirplanesAndRockets.com Please Support RF Cafe by purchasing my ridiculously low−priced products, all of which I created. RF Cascade Workbook RF & Electronics Symbols for Visio RF & EE Symbols Word RF Workbench (shareware) T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads These Are Available for Free Calculator Workbook Smith Chart™ for Excel