Wind Chill Calculator — In Javascript, Ruby, and PHP
Category: Blog

Since I spent the time to dig up the method of calculating the wind chill given a specific temperature and wind speed, I figured I would go ahead and share it in case someone else finds it useful. Here’s three functions for calculating the wind chill, one each for Javascript, PHP, and Ruby.

// Javascript version
// wind = wind speed in knots
// temp = temperature in Celsius
function getWindChill(wind, temp) {
   wind = wind * 1.852;
   var wind2 = Math.pow(wind, 0.16);
   var wind_chill = (13.12 + 0.6215 * temp - 11.37 * wind2 + 0.3965 * temp * wind2);
   wind_chill = parseFloat(wind_chill.toFixed(2));
   wind_chill = (wind <= 4.8) ? temp : wind_chill;
   wind_chill = (temp > 10) ? temp : wind_chill;
   return wind_chill;
}
// PHP version
// wind = wind speed in knots
// temp = temperature in Celsius
function getWindChill($wind, $temp) {
   $wind = $wind * 1.852;
   $wind2 = pow($wind, 0.16);
   $wind_chill = (13.12 + 0.6215 * $temp - 11.37 * $wind2 + 0.3965 * $temp * $wind2);
   $wind_chill = round($wind_chill, 2);
   $wind_chill = ($wind <= 4.8) ? $temp : $wind_chill;
   $wind_chill = ($temp > 10) ? $temp : $wind_chill;
   return $wind_chill;
}
# Ruby version
# wind = wind speed in knots
# temp = temperature in Celsius
def getWindChill(wind, temp)
   wind = (wind * 1.852)
   wind2 = wind**0.16
   wind_chill = (13.12 + 0.6215 * temp - 11.37 * wind2 + 0.3965 * temp * wind2)
   (temp > 10) ? temp : (wind <= 4.8) ? temp : (wind_chill * 100).round.to_f / 100
end

As you can see, pretty simple, but hopefully one will prove useful to someone someday.

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2 Responses to “Wind Chill Calculator — In Javascript, Ruby, and PHP”

  1. Mb says:

    Wind speed must be in km/h, not Knots

  2. Martin de M says:

    Thanks man, i was looking for this for my mobile app back end. Works great!

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