Wind Chill Calculator and Equations

Heat Transfer

Wind-chill or windchill, (popularly wind chill factor) is the perceived decrease in air temperature felt by the body on exposed skin due to the flow of air.

Wind chill numbers are always lower than the air temperature for values where the formula is valid. When the apparent temperature is higher than the air temperature, the heat index is used instead.

A measure of the cooling effect of wind. Wind increases the rate at which a body loses heat, so the air on a windy day feels cooler than the temperature indicated by a thermometer. This heat loss can be calculated for various combinations of wind speed and air temperature and then converted to a wind chill equivalent temperature (or wind chill factor).

Wind Chill Temperature °F = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16)

Where:

Where T = Air Temperature (F)
V = Wind Speed (mph)

Reference Machinery's Handbook 29th edition
NOAA

Notes:

Wind Chill is defined for temperatures within the range -45^oF to +45^oF and wind speeds 3 to 60 mph. Wind Chill temperature only will not cause water to freeze. Water will only freeze when the waters temperature reaches the freezing point.

Wind Speed, mph	Actual Thermometer Reading, °F
	50	40	30	20	10	0	10	20	30	40	50	60
	Equivalent Wind Chill Temperature, °F
0	50	40	30	20	10	0	10	-20	-30	-40	-50	-60
5	48	37	27	16	6	-5	-15	-26	-36	-47	-57	-68
10	40	28	16	3	9	-21	-34	-46	-58	-71	-83	-95
15	36	22	9	-5	-18	-32	-45	-59	-72	-86	-99	-113
20	32	18	4	-11	-25	-39	53	-68	-82	-96	-110	-125
25	30	15	0	-15	-30	-44	-59	-74	-89	-104	-119	-134
31	28	13	-3	-18	-33	-48	-64	-79	-94	-110	-125	-140
35	27	11	-4	-20	-36	-51	-67	-83	-98	-114	-129	-145
40	26	10	-6	-22	-38	-53	-69	-85	-101	-117	-133	-148

Little danger: In less than 5 h, with dry skin. Maximum
danger from false sense of security.

WCI < 1400

Increasing danger: Danger of
freezing exposed flesh within 1 min.
(1400 ≤WCI ≤2000)

Great danger: Flesh may freeze within 30 s.
(WCI > 2000)

Wind Reference Chart
(Click on image to enlarge)

Source

Source: U.S. Army Research Institute of Environmental Medicine.