The Finnish Meteorological Institute has a network of ten radars, which covers most of the country. In addition, data from neighbouring countries, obtained though the international exchange, improves the coverage especially on sea areas.
A radar sees the weather phenomena to a distance of 250 km in the Finnish climate. Therefore a network of several radars is needed to cover bigger land areas. The coverage depends on the weather conditions. Summer rain is seen to a distance of 250 km and more (outer line in the figure), and winterly snowfall to a distance of 120 km (circles in the figure).