Abstract: With monthly and annual dataset of thunderstorm and lightning measured at 24 stations from 1957 to 2004 and at 4 stations from 1951 to 2004 in Guangdong, the temporal and spatial distribution of thunderstorm and lightning in the province is studied. It is shown in the empirical orthogonal decomposition of the number of thunderstorm and lightning days there is a clear declining tendency in the number of both for the period of interest. For every 10 years, the thunderstorm has decreased by 4.8 days and lightning by 9.5 days on average. The trends of thunderstorm and lightning are regional, with the largest drop in Zhanjiang and Xuwen in the Leizhou Peninsula for thunderstorm while the least fall in the southeastern part of the province for both thunderstorm and lightning. The negative trend for lightning is more obvious than that for thunderstorm. As shown in our study, long-term tendency of thunderstorm and lightning days have significant seasonal variation. May, June, July, August and September are the months when thunderstorm and lightning drop the most while they increase a little in the winter months of December, January and February, instead of decreasing. After 1983, winter thunderstorm and lightning were more frequent than the time before it. The decrease of thunderstorm reflects the climate change and is consistent with the climatological variation of rain days in the province.