Ionospheric perdition studies are very few over Saudi Arabia due to less availability of data measurement. Although such kind of studies have been carried out all over the world, there still remains scope to ascertain prediction error in this country. Hence, in the current study, the ionospheric variation from April 2016 to February 2018 (almost 22 months) was studied over a GPS site HALY (29.140N; 36.10 0E), Al-Jouf, Saudi Arabia. Diurnal, monthly and seasonal ionospheric variations were investigated and compared with the existing global IRI (IRI 2012 and IRI 2016) models. Percentage deviation between observed and modeled TEC variation values indicated large-scale deviation around 200% during the time of storm. Results showed that the IRI 2012 model had the lowest Root Mean Square Error (RMSE) value (2.7437) during the September Equinox while IRI-2016 showed the highest RMSE magnitudes (3.0166) during the December Solstice. In some seasons, the RMSE values were observed to be better for IRI 2012 while on other occasions, it emerged that IRI 2016 yielded more accurate results. Such variations indicate that even the most updated version of the IRI 2016 model is unable to provide perfect estimation and the requirement of further research and improvement in this field cannot be denied.