Revised Wind Chill Index
The wind chill temperature index measures how cold people feel when outside. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature. The wind therefore makes it feel much colder. If the temperature is 0°F and the wind is blowing at 15 mph, the wind chill is –19°F. At this wind chill temperature, exposed skin can freeze in 30 minutes.
A revised wind chill table was introduced by the National Weather Service on Nov. 1, 2001. The new index was tested on human subjects and is based on heat loss from exposed skin. The old index, formulated in 1945 by Antarctic explorers, measured the cooling rate of water.
| Wind speed (mph) | Temperature (°F) | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 40 | 35 | 30 | 25 | 20 | 15 | 10 | 5 | 0 | –5 | –10 | –15 | –20 | –25 | –30 | –35 | –40 | –45 | |
| 5 | 36 | 31 | 25 | 19 | 13 | 7 | 1 | –5 | –11 | –16 | –22 | –28 | –34 | –40 | –46 | –52 | –57 | –63 |
| 10 | 34 | 27 | 21 | 15 | 9 | 3 | –4 | –10 | –16 | –22 | –28 | –35 | –41 | –47 | –53 | –59 | –66 | –72 |
| 15 | 32 | 25 | 19 | 13 | 6 | 0 | –7 | –13 | –19 | –26 | –32 | –39 | –45 | –51 | –58 | –64 | –71 | –77 |
| 20 | 30 | 24 | 17 | 11 | 4 | –2 | –9 | –15 | –22 | –29 | –35 | –42 | –48 | –55 | –61 | –68 | –74 | –81 |
| 25 | 29 | 23 | 16 | 9 | 3 | –4 | –11 | –17 | –24 | –31 | –37 | –44 | –51 | –58 | –64 | –71 | –78 | –84 |
| 30 | 28 | 22 | 15 | 8 | 1 | –5 | –12 | –19 | –26 | –33 | –39 | –46 | –53 | –60 | –67 | –73 | –80 | –87 |
| 35 | 28 | 21 | 14 | 7 | 0 | –7 | –14 | –21 | –27 | –34 | –41 | –48 | –55 | –62 | –69 | –76 | –82 | –89 |
| 40 | 27 | 20 | 13 | 6 | –1 | –8 | –15 | –22 | –29 | –36 | –43 | –50 | –57 | –64 | –71 | –78 | –84 | –91 |
| 45 | 26 | 19 | 12 | 5 | –2 | –9 | –16 | –23 | –30 | –37 | –44 | –51 | –58 | –65 | –72 | –79 | –86 | –93 |
| 50 | 26 | 19 | 12 | 4 | –3 | –10 | –17 | –24 | –31 | –38 | –45 | –52 | –60 | –67 | –74 | –81 | –88 | –95 |
| 55 | 25 | 18 | 11 | 4 | –3 | –11 | –18 | –25 | –32 | –39 | –46 | –54 | –61 | –68 | –75 | –82 | –89 | –97 |
| 60 | 25 | 17 | 10 | 3 | –4 | –11 | –19 | –26 | –33 | –40 | –48 | –55 | –62 | –69 | –76 | –84 | –91 | –98 |
See Weights and Measures for Fahrenheit and Celsius scales.
