anchor.diff:      + validFrom: `2016-12-13T11:00:00Z` (string, optional) - ISO8601 timestamp notation, means incl. this timestamp; always provide a time offset, e.g. 'Z' for UTC; optional: a request may provide correct offset (so that server can convert to UTC).
       + validUntil: `2016-12-13T12:00:00Z` (string, optional) - ISO8601 timestamp notation, means incl. this timestamp; always provide a time offset, e.g. 'Z' for UTC; optional: a request may provide correct offset (so that server can convert to UTC).
       + validPeriod: `PT0S,PT1H,PT3H,PT6H,PT12H,PT24H` (string, required) - comma separated list of periods to be retrieved. PT1H refers to one hour forecast periods.
  -
  +    + timeZone: `UTC` (string, optional) - a time-zone ID, such as `Europe/Paris`, `-01:00` etc.
  +	
   + Response 200 (application/json)
   
       + Headers
  
positive.code: The token will be in the return message, encrypted with a key from the authorization service.
  
  It will contain the client-ID, scopes and expiration date.
  The token is only a valid for a limited time, after this it will expired and you have to request a new token again.
  
  #### Using Authorization Token
  
  
negative.code: Whereas max air temperature is typically forecasted for a period of one our.
  There are other forecast periods possible, where parameters than are aggregated among e.g. 12 hours.
  In the response JSON document the weather parameters will be associated with their according period.
  
  If a user specifies the 'timeZone' parameter, `validFrom`, `validUntil` and all aggregated fields will be presented in this time zone.
  If a user doesn't specify 'timeZone' parameter, `validFrom`, `validUntil` and all aggregated fields will be presented either in a time zone 
  of a requested location or in a time zone of a meteo station (when requesting forecast by `locatedAt` or `meteoGroupStationIds` correspondingly).
  
  All aggregated parameters (e.g. `maxAirTemperatureInCelsius`) are calculated at fixed hours as follows:
  PT1H - every hour
  PT3H - at 00:00, 03:00, 06:00, 09:00, 12:00, 15:00, 18:00 and 21:00
  PT6H - at 00:00, 06:00, 12:00 and 18:00
  PT12H - at 06:00 and 18:00
  PT24H - at 00:00
  
  *Technical hints*
  
  