Wind chill

A katabatic blows snow off the plateau
A katabatic blows snow off the plateau (Photo: Glenn Browning)
Mawson expeditioner walks in the Katabatic WindMawson's Huts in a blizzard

Increased wind speed results in increased heat loss. This is called the wind chill factor. You can walk outside in shirt sleeves in minus 40°C if it is absolutely calm but you may require the thickest of layers at minus 5°C if the wind is above gale force. Even the wind generated by walking can cause frostbite; a gale at minus 40°C is dangerous.

The "sensation" scale - how you will feel at a given wind chill temperature.
Freezing cold below −25°C
Bitterly cold −25 to −15°C
Very cold −15 to −10°C
Cold −10 to 0°C
Very cool 0 to 10°C
Cool 10 to 15°C
Mild above 15°C

To calculate the wind chill factor use the following equation which is derived from the Nomogram of Rees, W.G. Polar Record 29 (170):229-234 (1993). The formula is:

[ -32 Ws /25 - Ts ] Twc = 2 [ ----------------- + Ts ] [ 2 + 1.5 Ws / 25 ]

where Twc = wind chill temperature, Ts is still air temperature and Ws is wind speed in metres/sec.

To make this easier, you can use the wind chill calculator.

The National Weather Service in the United States has developed a different formula for measuring wind chill. The NWS Wind Chill page has further information.

This page was last modified on 28 February 2003.