Sri Jayawardenepura Kotte sits in Sri Lanka’s southwestern wet zone, where the southwest monsoon from May through September brings the island’s heaviest rainfall, supplemented by a second wet spell during the October-to-December inter-monsoon period.
Sri Lanka’s official capital sits amid the Colombo wetlands, whose marshes play a key role in managing the region’s monsoon runoff. The catastrophic May 2017 floods and landslides, triggered by an intense burst of southwest monsoon rain, remain the reference event for how quickly this densely populated region can flood, and Sri Lanka’s Department of Meteorology relies heavily on radar to track incoming monsoon rain bands. Learn more: Flash Flood Warning Signs on Radar · Open the full Rain Map