The service is available for consumption for operational usage at this endpoint. Note that the user must set the apikey into the url at place APIKEY
Url
https://data.fmi.fi/fmi-apikey/APIKEY/timeseries?producer=wwi¶m=TopLinkIndex3,latitude,longitude,utctime&latlon=62,24&format=json×tep=data&starttime=data&endtime=data