Based on hourly precipitation observation data during the warm season(May to September) of 2005-2014 from 69 gauge stations in Jiangsu,the spatial and temporal distributions of short-time heavy rainfall(≥ 20 mm/h) have been analyzed,which showed obvious heterogeneity in space and time.The occurrence frequency of short-time heavy rainfall in northern Jiangsu area was higher than that in the southern region,and its most active region is located in the western area along Huaihe River.Meanwhile,extreme short-time rainfall events(≥ 50 mm/h) frequently occurred in the eastern Huaibei with concentrated rainfall distributions.The occurrence frequency of short-time heavy rainfall showed the decreasing trend in the past decade,especially in northern Jiangsu.In general,July was the most active month of short-time heavy rainfall,and the extreme short-time rainfall events occurred most frequently in August.The pentad short-time heavy rainfall evolved with the phase variations that the frequency of short-time heavy rainfall increased rapidly during Meiyu season with the peak in the second pentad of July,and then the frequency of extreme short-time rainfall events increased obviously during mid-summer and reached its peak in the third pentad of August.In average,the diurnal variations of short-time heavy rainfall showed a double-peak pattern,with the highest peak around 17:00 BST and the secondary peak around 07:00 BST,while extreme short-time heavy rainfall events tended to occur in the afternoon.The diurnal variations of short-time heavy rainfall also demonstrated obvious sub-seasonal variability and spatial differences.It had a single peak in early morning during Meiyu season and a single peak in the evening during mid-summer.From the south to the north of Jiangsu,the diurnal pattern evolved from a single peak to double and multiple peaks.The peak appeared mostly in the afternoon in the southern area of Huaihe River,while mainly appeared during the night to early morning in the northern area of Huaihe River.