Question About Windchill

[leicsnow]

Whenever I look at any online weather station, if the temperature is 9C (48F) or less, the 'wind chill'/feel like temperature is always something less like 6C. However, if it is 10C (50F) or more, the feel like temperature is ALWAYS the same as the real temperature. Why is this?

E.g. if the temperature is 10C, it says it feels like 10C also. Then if the temp drops to 9C the wind chill will go down to 6C or something.

[Backtrack]

Some stations have settings to not calculate wind chill if the temperature is above a certain level.

Either that, or there is simply just no wind?

[Summer of '47]

Windchill is regarded as insignificant at temperatures of 10 °C or higher, no matter what the wind strength or direction - for the sake of calculation at least even though our bodies might notice an effect. Same with heat index being disregarded below certain temperatures.

[Backtrack]

Yep, mine has a setting that's set by default to not calculate the wind chill if the temperature is at or above 10C.

I turned this off, it's always good to see the wind chill no matter what the temperature is.

[Summer of '47]

This is what Davis have to say about Windchill calculation on the Weatherlink software

the latest National Weather Service (NWS) formula was not designed for use above 40°F. The result of the straight NWS implementation was little or no chilling effect at mild temperatures. This updated version provides for reasonable chilling effect at mild temperatures based on the effects determined by Steadman (1979)

I think most of us would agree that we can perceive windchill above 40 °F ! Here's a chart which shows windchill using Steadman's formula even up to 20 °C

http://www.weather.o.../wind_chill.htm

I think 20 °C is a bit OTT, but clearly high winds from say the N or NE on a day at 15 °C gives a rather different feel to the same temp on a calm day.