The heat index is an apparent temperature, or a measure of how hot it feels when temperature and humidity are combined. The heat index is the mostly commonly used method of measuring heat. It is the result of extensive biometeorological studies. It takes into account many parameters including body size and shape, core and body surface temperatures, clothing and the skin's resistance to heat and moisture transfer. The heat index values used in National Weather Service forecasts and warnings, and in heat index tables assume an average size adult, with clothing, in the shade, with a 5-mph wind. Being in full sun or in an area with no air movement can significantly increase the apparent temperature.

		70	75	80	85	90	95	100	105	110	115	120	125	130	135	140
	100	72	80	91	108
	95	71	79	89	105
	90	71	79	88	102	122
	85	71	78	87	99	117
	80	71	78	86	97	113	136
	75	70	77	86	95	109	130
	70	70	77	85	93	106	124	144
	65	70	76	83	91	102	119	138
	60	70	76	82	90	100	114	132	149
	55	69	75	81	89	98	110	126	142
	50	69	75	81	88	95	107	120	134	150
	45	68	74	80	87	95	104	115	129	143
	40	68	74	79	86	93	101	110	123	137	151
	35	67	73	79	85	91	98	107	118	130	143
	30	67	73	78	84	90	96	104	113	123	135	148
	25	66	72	77	83	88	94	101	109	117	127	139
	20	66	72	77	82	87	93	99	105	112	120	130	141
	15	65	71	76	81	86	91	97	102	108	115	123	131
	10	65	70	75	80	85	90	95	100	105	111	116	123	131
	5	64	69	74	79	84	88	93	97	102	107	111	116	122	128
	0	64	69	73	78	83	87	91	95	99	103	107	111	117	120	125