Wind Chill Myths
2016-02-15 10:38:03.000 – Mike Carmon, Co-Director of Summit Operations
With the arrival of the coldest air of the winter season this weekend, we’ve received many questions, comments, etc., regarding temperatures and wind chills. The two values are very distinct and have important differences, so I’ll attempt to explain those differences right here!
Ambient Air Temperature (hereafter referred to as just “air temperature”): The degree of “hotness” or “coldness” of a substance, in this case, the air, as measured directly by a thermometer of some kind. The degree of “hotness” or “coldness” is dependent on the average speed or kinetic energy of the atoms and molecules within that substance.
Wind Chill Factor: As wind speed increases, the heat loss from exposed skin increases. The wind chill factor is a calculation of an apparent temperature that an individual with exposed skin would hypothetically “feel.” The higher the winds, the more efficiently heat is carried away from any surface—skin included.
Direct Measurement vs. Calculation:
Air temperature can be measured directly, using any type of thermometer. This is an absolute value; a distinct characteristic of the air.
Wind chill, on the other hand, is a calculated value from two distinct environmental factors: air temperature & wind speed. Wind chill cannot be directly measured, as it is not a distinct characteristic of the air.
Absolute vs. Conditional:
Air temperature is an absolute measurable value.
Wind chill is an apparent factor; that is, what the air temperature “feels like” when you add the wind to it. There is no instrument with which you can measure wind chill, and it is dependent on several factors, such as the presence of wind speed and exposed human skin.
Air temperature is the same for all objects exposed to a particular air mass at a certain moment in time.
Wind chill, however, is geared specifically towards human exposure.
All weather stations, including the Mount Washington Observatory, do not keep historical records of wind chills. In the realms of serious scientific studies and research, it is relatively unimportant.
When meteorologists at the Mount Washington Observatory report temperatures in any way, shape, or form, they are ALWAYS referring to ambient air temperature. A professional meteorologist will never pass off a wind chill as air temperature—it can be misleading and even dangerous to do so.
The statement “the temperature with the wind chill is…” is a misnomer. Temperature does not change because of an increase in wind speed. Although related, temperature and wind chill are two completely distinct environmental characteristics.
The moral of the story: Once you eliminate all exposed skin, the wind chill factor simply becomes a non-factor.
Mike Carmon, Co-Director of Summit Operations