In this study, long-term analyses of thunderstorm events occurring in Marmara Region airports were carried out. In the analyses made using airport reports, the events that occurred between 2001-2015 were evaluated in terms of annual, monthly and intra-day changes. While no particular trend was observed in the thunderstorm events annually, more thunderstorms occurred in the summer months after September. In intraday analyses, it was determined that the most thunderstorm events occurred in the 2nd time zone (1100-1900 UTC). Rain also occurred 72% of the times when thunderstorms occurred. The rate of thunderstorm events that occurred without precipitation is 22%. One of the most important results of the study is that the convective available potential energy (CAPE) value was found to be zero in approximately 50% of the thunderstorm events. Non-zero CAPE values were also found to occur mostly (about 90%) in the range of 0 J/kg-1,000 J/kg.