Estimations of global solar radiation based on a model of using normalized clearness index and normalized sunshine duration for a period of up to 25 years for Ikeja (06.39°N, 03.20°E), Enugu (06.28 0 N, 07.35 0 E), and Kano (12.03 N, 08.32E), Nigeria for each climatological stations were established. The monthly average total solar radiation was also estimated. The reliability index of the calculation varies from 2.4 to 2.6 percent. The overall results show that for Kano, the received radiation on the plane surface is higher than for Ikeja and Enugu.