PV modules are tested by their manufacturers at STCs of 1000W/m2 solar irradiance and 25oC module temperature. However, the actual operating conditions of theses modules, usually vary from the STCs. In this work, climate data recorded for 8 cities of Nigeria have been used to stimulate the module temperatures and electrical outputs of 3 module types of 100W each. The results gotten were analyzed and the cities with high ambient temperature and low wind speed had high module temperature, lower Voc and efficiency, than the cities with lower ambient temperature and higher wind speed. High solar irradiation cities recorded high Isc and max power. The stimulated results were used to estimate the pv array size for a typical Nigerian home and values compared with RETScreen results.