Unfortunately the values for 'temperature' and 'dewpoint' which are returned are 7 and 26. These values are returned from METAR R07/2600U and stand for something like Runway 07 and visibility 2600.
The correct temperate and dewpoint are 0 and -1 (METAR 00/M01).
As a result it seems the 'humidity'-calculation also returns a wrong value?