This paper studies the use of polynomial fitting to model the global solar radiation that was measured by using solarimeter at Universiti Teknologi PETRONAS (UTP), located in Perak, Malaysia. The measured solar radiation data was filtered by using fitting and smoothing methods. The polynomial data fitting method was used for data smoothing and was tested by using different degrees of polynomial curve fittings. The error measurement was calculated by using the root mean square error (RMSE) and by determining the R2 value. The polynomial fittings were carried out by using MATLAB. © 2014 Samsul Ariffin Abdul Karim and Balbir Singh Mahinder Singh.