The spatial and diurnal variation of rainfall over Asia was investigated using the spaceborne radar data for four seasons during 1998--2003. The regional variation of the prevailing precipitation systems most closely associated with the maximum hourly rainfall was shown by examining the fine spatial distribution of rainfall amount and scale-based precipitation systems. Small precipitation systems (104 km2) developed mostly in the evening over nearly flat landmasses. Wide-spread systems with intense rain pixels developed over the foothills of the Himalayas in late night--early morning period, which was distinct from the daytime convection. Over ocean, in addition to the morning signature, spatially inhomogeneous and systematic characteristics were evident over the offshore region, for example, around the maritime continent. Large systems, which are strongly associated with terrain, have a great influence on the total number of rain pixels and the total amount of rainfall. For 86% of the region where large system is dominant the time of maximum rainfall is within 3 hours of the time of maximum rainfall for large systems.