A forecasting system is provided with: a sun-direction-cloudiness calculation means 101 for calculating sun-direction cloudiness on the basis of the degree of cloudiness of cells when the sky above a specified location is divided so as to include two or more cells along the height direction, the sun-direction cloudiness being the degree of cloudiness in the direction of the sun at a designated first location; and a forecasting means 102 for forecasting a forecasted value using the sun-direction cloudiness, the forecasted value being a category pertaining to solar energy. The degree of cloudiness of the cells may be the degree of cloudiness of the cells when the surface of the ground including the first location, together with the sky above said surface, is divided so as to include two or more cells along the horizontal direction in addition to including two or more cells along the height direction. It is permissible for the sun-direction-cloudiness calculation means 101 to calculate the sun-direction cloudine
