Säädata

Säädata, or weather data, refers to measurements, observations, forecasts and derived information about atmospheric conditions and related phenomena. It is collected, processed and stored to support weather forecasting, climate research and a wide range of practical applications. Data originate from both ground-based and spaceborne sources and are produced by national meteorological services, research institutions and international networks.

Common components of säädata include observational data such as temperature, humidity, air pressure, wind, precipitation and cloud cover; radar and satellite observations; and derived products like visibility, dew point and accumulated precipitation. In addition, numerical weather prediction models produce forecast fields and ensemble forecasts, while reanalysis datasets combine observations with models to provide consistent historical climate information. Data are stored in standard formats (for example GRIB or NetCDF for gridded fields, and CSV for tabular records) and are accompanied by metadata describing provenance, quality control and uncertainty. International norms and guidelines, notably from the World Meteorological Organization (WMO), guide data formats, exchange and quality assurance.

Data access and dissemination vary by country and institution. In Finland, the Finnish Meteorological Institute (FMI) collects säädata and distributes it through national portals and services, with many datasets offered as open data via APIs. Internationally, data are shared through collaborations within EUMETNET, WMO networks and other open data initiatives. Licensing is often permissive to support broad reuse, though distinctions between real-time operational data and historical or specialized datasets exist.

Säädata underpins forecasting accuracy, climate monitoring and decision-making in sectors such as aviation, shipping, agriculture, energy and emergency management, making timely, reliable data essential for society.