Weather forecast consists on collecting, analysing and interpreting the different observation products, direct measurements or from remote sensing sources, as well as the products of the models of numerical weather prediction.

It proceeds 24 hours a day, 7 days a week, and the weather forecasts are provided in the form of bulletins, directives, or files in the various communication supports.

Forecasts are established for periods of a few hours up to 6 days. A distinction is made between very short and short-range for the next 24 or 48 hours and medium-range for the next 3 to 6 days.

Different economic sectors are interested in forecast bulletins (aeronautical and marine services, agriculture, industry, environment, energy , and tourism) and other fields like health, sports, recreation, and media.