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# Apparent temperature

This online calculator computes apparent temperature, taking into consideration wind speed and relative air humidity. It uses Australian Bureau of Meteorology formula

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So calculator about Wind Chill Index can tell us how cold is on the wind. But there is another important formula which can define human thermal comfort, called the Apparent Temperature (AT). AT is a heat index invented in Australia by a researcher named Robert Steadman, his work was published in 1984. It takes into consideration four environmental factors: wind, temperature, humidity and radiation from the sun.

The formula for the AT is:
$AT=T_a+0.348*e-0.70*ws+0.70\frac{Q}{ws+10}-4.25$
where
Ta = Dry bulb temperature (°C)
e = Water vapour pressure (hPa) [humidity]
ws = Wind speed (m/s) at an elevation of 10 meters
Q = Net radiation absorbed per unit area of body surface (W/m2)

E is computed like this
$e=\frac{rh}{100}*6.105*e^{\frac{17.27*T_a}{237.7+T_a}}$
where
rh = Relative Humidity [%]

While temperature and humidity are regional and seasonal factors, wind and radiation are microclimatic factors and are influenced by local environment. I think that it is quite hard to measure or estimate radiation, so I do not use radiation term, thus this calculator computes apparent temperature for outdoors in the shade. Also it plots dependency of apparent temperature on humidity.

### Apparent temperature

Digits after the decimal point: 1
Apparent temperature, Celsius

Humidity dependency