Many parameters and environments conditions will affect the behavior of the photovoltaic cell. This paper investigates, theoretically the variation of each temperature and irradiation effects on the output of the photovoltaic cell characteristics. Modeling of the photovoltaic cell scheme essentially requires taking weather data (temperature and irradiance) as input variables. The photovoltaic outputs are the current, voltage and power. Though, conclude the characteristics I-V or P-V desires of these important variables. Any variation in the entries directly shows variations in outputs. The characteristic curves are obtained with the use practical readings and measurements are illustrated directly from the solar power plant in the Technical Engineering College of Mosul. The complete modeling is then computer-generated using MATLAB/Simulink software owing to its common use and its helpfulness.