Wind Chill/Heat Index Chart

Wind Chill Chart

The wind chill index provided below shows the effective cooling on exposed skin. When the wind blows across the skin, it removes the insulating layer of warm air adjacent to the skin. When all factors are the same, the faster the wind blows, the greater the heat loss, which results in a colder feeling.

Wind Speed-mph

Calm 5 10 15 20 25 30 35

Temperature
(Degrees F) Wind Chill

45 43 34 29 26 23 21 20

40 37 28 23 19 16 13 12

35 32 22 16 12 8 6 4

30 27 16 9 4 1 -2 -4

25 22 10 2 -3 -7 -10 -12

20 16 3 -5 -10 -15 -18 -20

15 11 -3 -11 -17 -22 -25 -27

10 6 -9 -18 -24 -29 -33 -35

5 0 -15 -25 -31 -36 -41 -43

0 -5 -22 -31 -39 -44 -49 -52

-5 -10 -27 -38 -46 -51 -59 -64

-10 -15 -34 -45 -51 -59 -64 -67

-15 -21 -40 -51 -60 -66 -71 -74

-20 -26 -46 -58 -67 -74 -79 -82

-25 -31 -52 -65 -74 -81 -86 -89

If you would like to calculate the wind chill index for combinations of temperature and wind other than those given in the table above, you can use the formula:

Wind Speed-mph
Calm	5	10	15	20	25	30	35
Temperature (Degrees F)	Wind Chill
45	43	34	29	26	23	21	20
40	37	28	23	19	16	13	12
35	32	22	16	12	8	6	4
30	27	16	9	4	1	-2	-4
25	22	10	2	-3	-7	-10	-12
20	16	3	-5	-10	-15	-18	-20
15	11	-3	-11	-17	-22	-25	-27
10	6	-9	-18	-24	-29	-33	-35
5	0	-15	-25	-31	-36	-41	-43
0	-5	-22	-31	-39	-44	-49	-52
-5	-10	-27	-38	-46	-51	-59	-64
-10	-15	-34	-45	-51	-59	-64	-67
-15	-21	-40	-51	-60	-66	-71	-74
-20	-26	-46	-58	-67	-74	-79	-82
-25	-31	-52	-65	-74	-81	-86	-89

WC = 91.4 - (0.474677 - 0.020425 * V + 0.303107 * SQRT(V)) * (91.4 - T)

       where:
              WC = wind chill index
              V = wind speed (mph)
              T = temperature (° F)

Heat Index Chart

The NWS has devised the "HEAT INDEX" (HI), sometimes called the "apparent temperature." The HI is the temperature the body feels when the heat and humidity are combined. The table below is the Heat Index Chart. (Note: This chart is based upon shady, light wind conditions. Exposure to full sunshine can increase HI values by up to 15° F.)

Air Temperature (Degrees F)

70 75 80 85 90 95 100 105 110 115 120

Relative
Humidity Heat Index

0% 64 69 73 78 83 87 91 95 99 103 107

10% 65 70 75 80 85 90 95 100 105 111 116

20% 66 72 77 82 87 93 99 105 112 120 130

30% 67 73 78 84 90 96 104 113 123 135 148

40% 68 74 79 86 93 101 110 123 137 151

50% 69 75 81 88 96 107 120 135 150

60% 70 76 82 90 100 114 132 149

70% 70 77 85 93 106 124 144

80% 71 78 86 97 113 136 157

90% 71 79 88 102 122 150 170

100% 72 80 91 108 133 166

	Air Temperature (Degrees F)
70	75	80	85	90	95	100	105	110	115	120
Relative Humidity	Heat Index
0%	64	69	73	78	83	87	91	95	99	103	107
10%	65	70	75	80	85	90	95	100	105	111	116
20%	66	72	77	82	87	93	99	105	112	120	130
30%	67	73	78	84	90	96	104	113	123	135	148
40%	68	74	79	86	93	101	110	123	137	151
50%	69	75	81	88	96	107	120	135	150
60%	70	76	82	90	100	114	132	149
70%	70	77	85	93	106	124	144
80%	71	78	86	97	113	136	157
90%	71	79	88	102	122	150	170
100%	72	80	91	108	133	166

Heat Index Readings and Potential Heat Related Disorders:
85 to 94 degrees F - Caution: physical activity may cause fatigue
95 to 105 degrees F - Extreme Caution: possible heat cramps and/or heat exhaustion with prolonged exposure
Above 105 degrees F - Danger: possible heat stroke with prolonged exposure; heat exhaustion and heat cramps likely