| public static calculateDewPoint ( double $temperature, double $humidity ) : double | ||
| $temperature | double | Temperature in degrees C. |
| $humidity | double | Humidity. |
| return | double | |
public static function calculateDewPoint($temperature, $humidity)
{
if ($temperature >= 0) {
$a = 7.5;
$b = 237.3;
} else {
$a = 7.6;
$b = 240.7;
}
// First calculate saturation steam pressure for temperature
$SSP = 6.1078 * pow(10, $a * $temperature / ($b + $temperature));
// Steam pressure
$SP = $humidity / 100 * $SSP;
$v = log($SP / 6.1078, 10);
return $b * $v / ($a - $v);
}