 As the wind blows, it takes heat away from your body, making the temperature feel much colder than the thermometer says it is. This effect is called wind chill. The wind chill factor is figured by comparing the current wind speed and temperature readings on a special wind chill chart. The lower the wind chill factor, the colder you feel and the sooner you can develop cold-based injuries such as frostbite. The wind chill chart was updated in 2001 by the National Weather Service. The old wind chill chart used by the NWS was based on the 1945 Siple and Passel Index. When checking wind chill, be sure that you are using the updated chart. The National Weather Service has a page dedicated to the new wind chill information.
Measuring the Wind Chill
To determine the wind chill factor, you will need to know the wind speed and dry-bulb (air) temperature. Once you have this information, go to the wind chill chart. The wind speed is listed vertically (down the left side) and the dry-bulb temperature is listed horizontally (across the top). The intersection of those readings is the wind chill factor. |
