# @param [Float] temp_c temperature in C
# @param [Float] humidity in percent, 0-100
def dewpoint(temp_c, humidity)
    l = Math.log(humidity / 100.0)
    m = 17.27 * temp_c 
    n = 237.3 + temp_c 
    b = (l + (m / n)) / 17.27
    dewpoint_c = (237.3 * b) / (1 - b)
end