<p>Wind chill is only relevant for cold temperatures. During hot temperatures, the affect of wind is to increase the felt temperatures.</p>
<p>What would be more appropriate would be <a href="https://media.bom.gov.au/social/blog/1153/apparent-feels-like-temperature/" rel="noreferrer">apparent temperature</a>, also known as the &quot;<a href="https://en.wikipedia.org/wiki/Wind_chill#Australian_apparent_temperature" rel="noreferrer">feels like</a>&quot; temperature. This calculated temperature considers the effect of the dry bulb temperature, humidity and wind speed.</p>
<blockquote>
<p><span class="math-container">$ {\displaystyle \mathrm {AT} =T_{\mathrm {a} }+0.33e-0.7v-4.00}$</span></p>
<p>where:</p>
<p>T<sub>a</sub> = dry bulb temperature (°C)</p>
<p>e = water vapour pressure (hPa)</p>
<p>v = wind speed (m/s) at an elevation of 10 m</p>
<p>The vapour pressure can be calculated from the temperature and relative humidity using the equation:</p>
<p><span class="math-container">$e = \frac{R H}{100} ⋅ 6.105 ⋅ exp ( \frac{17.27 ⋅ T a}{ 237.7 + T a} ) $</span></p>
<p>Where:</p>
<p>T<sub>a</sub> = dry bulb temperature (°C)</p>
<p>RH = Relative humidity (%)</p>
<p><span class="math-container">$exp$</span> represents the exponential function</p>
<p>The Australian formula includes the important factor of humidity and is somewhat more involved than the simpler North American model.</p>
</blockquote>

CC BY-SA 4.0
2022-08-02T14:26:18.560Z
Related: http://www.bom.gov.au/jshess/docs/1994/steadman.pdf
Joscha Fregin
CC BY-SA 4.0
2022-08-02T22:19:51.157Z
@Fred Is this formula the same as the heat index formula? Also, is this going to work considering that I don't live at an altitude of ten meters? I live at an altitude of 44 meters.
cowboydaniel
CC BY-SA 4.0
2022-08-02T23:04:25.413Z
I presume this means the data to support this formula were collected with an anemometer 10 feet off the ground.   The wind speed at ground level would probably be slower and more variable.
BowlOfRed
CC BY-SA 4.0
2022-08-03T01:45:23.573Z
@DanielVanNattan: The [Heat Index](https://en.wikipedia.org/wiki/Heat_index), used in the USA, is a similar measure, based in the Steadman Apparent Temperature, but the equation has a lot more terms. The [Heat Index](https://en.wikipedia.org/wiki/Apparent_temperature) measures the effect of humidity on the perception of temperatures **above +27 °C (81 °F)**. In humid conditions, the air feels much hotter, because less perspiration evaporates from the skin.
Fred
CC BY-SA 4.0
2022-08-03T18:03:57.050Z
@cowboydaniel: The elevation of 10 m for the wind speed, is not elevation above sea level. It is the height above the ground. ["A common anemometer height for meteorological measurements is 10m"](https://www.homerenergy.com/products/grid/docs/1.5/anemometer_height.html) .
Fred
CC BY-SA 4.0
2022-08-02T12:49:35.233Z
2022-08-02T12:49:35.233Z
Fred
<p>I'm looking for a wind chill formula that will work from -10 °C to +50 °C and uses wind speed in km/h so that I can use this formula to add this element to a weather station I am programming. I don't need it in code, just the normal math formula will work. I couldn't find this exact formula on google, and I am hoping someone here will know.</p>

CC BY-SA 4.0
2022-08-02T11:02:55.420Z
Not sure it exists at the range you're looking for. "Windchill temperature is defined only for temperatures at or below 10 °C (50 °F) and wind speeds above 4.8 kilometres per hour (3.0 mph)." From https://en.wikipedia.org/wiki/Wind_chill#North_American_and_United_Kingdom_wind_chill_index
Jean-Marie Prival
CC BY-SA 4.0
2022-08-02T12:51:30.390Z
https://www.weather.gov/media/epz/wxcalc/windChill.pdf has the formula the US govt uses. As others have noted, wind chill doesn't really apply above 10C. Quoting the site that links to the PDF, https://www.weather.gov/epz/wxcalc_windchill "The wind chill calculator only works for temperatures at or below 50 ° F and wind speeds above 3 mph."
Barry Carter
CC BY-SA 4.0
2022-08-02T20:00:58.413Z
Having lived in Montreal (where -10 °C is a pleasant winter day) and Dallas, (where the average high temperature in July 2022 was just over 39 °C), I can tell you that a windy day when it's 40 °C "feels like" _oven_, not _chill_
Flydog57
<meteorology><temperature><weather-forecasting><wind>
What is a wind chill formula that will work from -10 C to +50 C and uses wind speed in km/h?
cowboydaniel
# What is a wind chill formula that will work from -10 C to +50 C and uses wind speed in km/h?

(Asked by: username_0 on 2022-08-02)

I'm looking for a wind chill formula that will work from -10 °C to +50 °C and uses wind speed in km/h so that I can use this formula to add this element to a weather station I am programming. I don't need it in code, just the normal math formula will work. I couldn't find this exact formula on google, and I am hoping someone here will know.

**Tags:** meteorology, temperature, weather-forecasting, wind

> **Comments:**
> **username_1**: Not sure it exists at the range you're looking for. "Windchill temperature is defined only for temperatures at or below 10 °C (50 °F) and wind speeds above 4.8 kilometres per hour (3.0 mph)." From https://en.wikipedia.org/wiki/Wind_chill#North_American_and_United_Kingdom_wind_chill_index  
> **username_2**: https://www.weather.gov/media/epz/wxcalc/windChill.pdf has the formula the US govt uses. As others have noted, wind chill doesn't really apply above 10C. Quoting the site that links to the PDF, https://www.weather.gov/epz/wxcalc_windchill "The wind chill calculator only works for temperatures at or below 50 ° F and wind speeds above 3 mph."  
> **username_3**: Having lived in Montreal (where -10 °C is a pleasant winter day) and Dallas, (where the average high temperature in July 2022 was just over 39 °C), I can tell you that a windy day when it's 40 °C "feels like" _oven_, not _chill_  

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## 1 answers

### Answer by username_4 on 2022-08-02. Score: 9

Wind chill is only relevant for cold temperatures. During hot temperatures, the affect of wind is to increase the felt temperatures.

What would be more appropriate would be [apparent temperature](https://media.bom.gov.au/social/blog/1153/apparent-feels-like-temperature/), also known as the "[feels like](https://en.wikipedia.org/wiki/Wind_chill#Australian_apparent_temperature)" temperature. This calculated temperature considers the effect of the dry bulb temperature, humidity and wind speed.

> $ {\displaystyle \mathrm {AT} =T\_{\mathrm {a} }+0.33e-0.7v-4.00}$
>
> where:
>
> Ta = dry bulb temperature (°C)
>
> e = water vapour pressure (hPa)
>
> v = wind speed (m/s) at an elevation of 10 m
>
> The vapour pressure can be calculated from the temperature and relative humidity using the equation:
>
> $e = \frac{R H}{100} ⋅ 6.105 ⋅ exp ( \frac{17.27 ⋅ T a}{ 237.7 + T a} ) $
>
> Where:
>
> Ta = dry bulb temperature (°C)
>
> RH = Relative humidity (%)
>
> $exp$ represents the exponential function
>
> The Australian formula includes the important factor of humidity and is somewhat more involved than the simpler North American model.

> **Comments:**
> **username_5**: Related: http://www.bom.gov.au/jshess/docs/1994/steadman.pdf  
> **username_0**: @username_4 Is this formula the same as the heat index formula? Also, is this going to work considering that I don't live at an altitude of ten meters? I live at an altitude of 44 meters.  
> **username_6**: I presume this means the data to support this formula were collected with an anemometer 10 feet off the ground.   The wind speed at ground level would probably be slower and more variable.  
> **username_4**: @DanielVanNattan: The [Heat Index](https://en.wikipedia.org/wiki/Heat_index), used in the USA, is a similar measure, based in the Steadman Apparent Temperature, but the equation has a lot more terms. The [Heat Index](https://en.wikipedia.org/wiki/Apparent_temperature) measures the effect of humidity on the perception of temperatures **above +27 °C (81 °F)**. In humid conditions, the air feels much hotter, because less perspiration evaporates from the skin.  
> **username_4**: @username_0: The elevation of 10 m for the wind speed, is not elevation above sea level. It is the height above the ground. ["A common anemometer height for meteorological measurements is 10m"](https://www.homerenergy.com/products/grid/docs/1.5/anemometer_height.html) .  

---

