This procedure provides a normative equation for analytically deriving a set of data points or a curve of irradiance versus time of day for a synthetic solar day. The coefficients of the normative equation for the analytical solar irradiance profiles are determined from measured or estimated values of maximum solar irradiance, daily solar irradiation and the number of daylight hours. These three input data define the curve of the analytical solar irradiance profiles. Depending on the objectives, these data may represent, for example, the worst winter day of a certain place, or the average day of a summer season, etc. CAUTION – While the results from the normative equation match measured clear sky data reasonably well, it is not intended to predict or simulate a real day. A daily solar irradiance profile is defined based on user-selected values for peak irradiance, daily irradiation and total daylight hours.