3. Wind Chill
• Is a measure how you feel in the cold, taking
in consideration of the influence of winds.
• There are a lot of misconceptions. For
example, if the temperature is 35F and the
wind chill is 29F, will water freeze?
4. Wind Chill
The first wind chill
formulas and tables
were developed by Paul
Allman Siple and Charles
F. Passel working in the
Antarctic before
the Second World War,
and were made available
by the National Weather
Service in the 1970s.
5. Measured cooling rates of bottles of
water for various combinations of
temperature and wind
6. Cooling depends on two things
• Difference in temperature between bottle (or
skin) and the environmental air
• Wind speed, which controls how quickly cold
air is mixed down to the bottle/skin, and how
rapidly warm air near bottle/skin is moved
away.
7. Led to Wind Chill Formula Estimating Loss
of Heat as a Function of Tempeature and
Wind Speed
