anchor.diff:                  "meteoGroupStationName": "Germ",
                   "stationLocation": [ 13.2323, 52.4593 ],
                   "stationTimeZoneName": "Europe/Berlin",
  -                "observedFrom": "2016-10-14T21:00:01Z",
  -                "observedUntil": "2016-10-15T09:00:01Z",
  +                "observedFrom": "2016-10-14T21:00:00Z",
  +                "observedUntil": "2016-10-15T09:00:00Z",
                   "observedPeriod": "PT12H",
                   "temperatureMaxInCelsius": 16.5,
                   "temperatureMaxInFahrenheit": 61.7,
  
positive.code:                 "meteoGroupStationName": "Germ",
                  "stationLocation": [ 13.2323, 52.4593 ],
                  "stationTimeZoneName": "Europe/Berlin",
                  "observedFrom": "2016-10-15T03:00:01Z",
                  "observedUntil": "2016-10-15T09:00:01Z",
                  "observedPeriod": "PT6H",
                  "precipitationAmountInMillimeter": 0.1,
                  "precipitationAmountInInch": 0.004
  
negative.code:                 "meteoGroupStationName": "Germ",
                  "stationLocation": [ 13.2323, 52.4593 ],
                  "stationTimeZoneName": "Europe/Berlin",
                  "observedFrom": "2016-10-15T06:00:00Z",
                  "observedUntil": "2016-10-15T09:00:00Z",
                  "observedPeriod": "PT3H",
                  "pressureChangeInHectoPascal": 2.0,
                  "pressureTendencyCode": 1,
  