The main goal of this study is analyzing the efficiency of GFS gridded data in identifying the temporal and spatial distribution of thunderstorm events in Iran. In the period of 10 years (2007-2016), 14 days of April and May were selected based on the highest storm events. Indexes of KI, LI and TT are computed in grid points to analyze instability condition over Iran and ArcGIS software is used to interpolation by Kriging method. The result shows that the LI index in each selected 14 days and the KI in 12 days have very consistent with highest thunderstorms reported in the stations. KI is observed in two days (29/04/2010 and 27/05/2014) and TT in two days (29/04/2010 and 19/05/2011), don’t have confidence with all reported thunderstorms but more stations show confidence with instability conditions in these days.