Abstract:Based on the high density precipitation data of automatic weather stations (AWS), the spatial temporal characteristics of extremely intensive precipitation on 21and 22 July 2012 over the Beijing area are analyzed. The results show that during the rainstorm, there were 211 stations recorded greater than 100 mm cumulative rainfall except for Yanqing Station, 96 stations recorded greater than 200 mm cumulative precipitation, and 12 stations greater than 300 mm. In most regions, the durations of precipitation were above 16 hours, with the largest in the southwestern Beijing, and the secondary in the northeast of Beijing. The average precipitation intensity exceeded 16 mm/h in Fangshan, and 14 mm/h in northeastern parts of the urban zone, in spite of the fact that precipitation intensities were less than 6 mm/h in the mountains of the north and northwest. The maximum hourly precipitation intensity was found in the northeast of Beijing and the second in the southwest. The larger average precipitation intensities occurred during 18:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗21:00 of 21 July, with the maximum of 22 mm/h recorded at 19:00 Abnormally strong precipitation intensities of more than 70 mm/h appeared during 19:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗22:00 over the whole city and 13:00〖KG-*3〗〖CD*2/3〗〖KG-*9〗14:00 at Longquan Station. The analysis also shows that the 24 h maximum precipitation of Fangshan on 21 July 2012 ranks the second for the time period of 1961 to 2012 The average 24 h maximum precipitation of 15 stations broke the record of Beijing since 1961, much larger than the second (9 August 1963).