anchor.diff:                  {
                       "meteoGroupStationId": "3002",
                       "meteoGroupStationName": "Baltasound",
  -                    "observedAt": "2017-03-03T00:00:00Z"
  +                    "observedAt": "2017-03-04T06:00:00Z"
  +                }
  +            ],
  +            "maxPrecipitationAmountInMillimeters": 1.5,
  +            "maxPrecipitationAmountObservations": [
  +                {
  +                    "meteoGroupStationId": "3002",
  +                    "meteoGroupStationName": "Baltasound",
  +                    "observedAt": "2017-03-04T06:00:00Z"
                   }
               ]
             },
  
positive.code:                 "meteoGroupStationName": "Baskervilles",
                  "observedAt": "2017-03-07T00:00:00Z"
                }
              ],
              "maxSunshineDurationInMinutes": 123,
              "maxSunshineDurationObservations": [
                  {
                      "meteoGroupStationId": "3002",
                      "meteoGroupStationName": "Baltasound",
                      "observedAt": "2017-03-07T00:00:00Z"
                  }
              ]
            }
          ]
        }
  
  #### Description
  The first element in the array contains extreme values for seven days, every next one - data for the individual days.  
  Here `observedUntil` and `observedFrom` fields represent period that has been used for extreme values calculation.
  Because extreme values recalculate every hour, difference between `observedUntil` value and time of the request can be up to 1 hour.
  The fields `minAirTemperatureObservations`, `maxAirTemperatureObservations`, `maxWindSpeedObservations`, `maxWindGustObservations` and `maxSunshineDurationObservations` are arrays that contain information about station where extreme value has been found and time where it has been observed.
  Because inside period the same extreme values can be observed many times, the arrays can contain many weather observations.
  
  The extreme values recalculating algorithm based on the following:
  
negative.code:                 {
                      "meteoGroupStationId": "3002",
                      "meteoGroupStationName": "Baltasound",
                      "observedAt": "2017-03-02T06:00:00Z"
                  }
              ],
              "maxPrecipitationAmountInMillimeters": 1.2,
              "maxPrecipitationAmountObservations": [
                  {
                      "meteoGroupStationId": "3002",
                      "meteoGroupStationName": "Baltasound",
                      "observedAt": "2017-03-02T06:00:00Z"
                  }
              ]
            },
  