In this study, using monthly, quarterly and annual frequency data of days with thunderstorm of 25 long-term synoptic weather stations during the period 1960-2010 were analyzed. In addition, temporal analysis of thunderstorms was performed using ward's hierarchical cluster analysis the square Euclidean distance and Mann-Kendall non-parametric test. According to the results of cluster analysis, three climate regions with similar trends in the frequency of thunderstorms were identified which included North West and North-central, western and northeastern regions, southern part, the Caspian Sea coastal regions and central and eastern parts of the country. The results of temporal analysis of thunderstorm days in Iran showed that in terms of frequency, monthly occurrence of this phenomenon is mostly in May, April, June and October and transitional seasons of spring and autumn. In contrast, the lowest frequency of thunderstorm days is in August, September and January, and in summer and winter seasons. Moreover, considering the location, in monthly, seasonal and annual intervals, thunderstorms had higher frequency in the North West and West regions than compared to other regions of Iran. The trend of thunderstorms variation also indicates that changes in monthly, seasonal and annual time scales had an upward trend and based on Mann-Kendall test results, they were significantly meaningful.