As the 2026 El Niño phenomenon intensifies, the Kenya Meteorological Service Authority (KEMSA) has warned Kenyans to prepare for above-average rainfall from the last week of September through December.
In its October-December weather outlook released on Wednesday, August 26, Kenya Met projected very heavy rains across the country, with an increased risk of flooding and landslides.
The weather department forecast above-average rainfall in all 47 counties, with rainfall intensity expected to increase gradually, particularly in Central Kenya, the Rift Valley, the Lake Victoria Basin and Western Kenya.
Some counties are expected to receive the rains as early as September, while others will experience the onset from the second week of October. "According to the most recent update, the 2026 El Niño event continues to intensify across the central-eastern equatorial Pacific," KEMSA announced.
Counties expected to begin receiving rains in September include Nandi, Kakamega, Vihiga, Bungoma, Siaya, Busia, Baringo, Nakuru, Trans Nzoia and Uasin Gishu.
The same rainfall pattern is expected in Elgeyo-Marakwet, West Pokot, Kisii, Nyamira, Kericho, Bomet, Kisumu, Homa Bay, Migori and Narok.
In Central Kenya, Nyandarua, Laikipia, Nyeri, Kirinyaga, Murang'a, Kiambu, Meru, Embu and Tharaka-Nithi are expected to experience the onset during the second and third weeks of October. Nairobi is also expected to receive the rains during the same period.
Coastal counties, including Mombasa, Kwale, Lamu, Kilifi and the Tana Delta, as well as northern counties such as Marsabit, Mandera, Wajir, Garissa and Isiolo, are expected to follow a similar timeline.
Machakos, Kitui, Makueni, Kajiado, Taita-Taveta and inland parts of Tana River County are projected to receive moderate to heavy rains from the third and fourth weeks of October.
Kenya Met also forecast warmer-than-average temperatures during the October-December season, with the highest temperatures expected along the Coast and in northern Kenya.
"The warm temperatures are due to the southward migration of the Intertropical Convergence Zone (ITCZ) that is associated with warm, humid air," the weather department explained.
Nairobi Steps Up Flood Preparedness
The forecast comes as Nairobi County implements a multi-agency preparedness plan ahead of the anticipated El Niño rains. Governor Johnson Sakaja announced that Ksh2.4 billion had been allocated for drainage and flood-mitigation projects across the capital.
The governor brought together representatives from the Kenya Red Cross, Kenya Urban Roads Authority (KURA), Kenya National Highways Authority (KeNHA), National Disaster Management Authority, Nairobi County Disaster Management Team, Environment Department and Nairobi Rivers Commission at City Hall on Monday, August 17.
The meeting established five specialised committees to coordinate preparedness, emergency response and public communication. “This calls for us to prepare together, act early and protect lives and property,” Sakaja said.
Of the Ksh2.4 billion allocation, Ksh2 billion will finance drainage and flood-control works targeting 19 roads identified as vulnerable to flooding. The county has already awarded tenders for the projects, with contractors expected to commence work after completing the required processes.
Sakaja maintained that the projects were intended to address Nairobi's long-standing drainage challenges rather than provide temporary solutions.
“The Ksh2 billion will support a comprehensive drainage overhaul that complements the ongoing Nairobi Regeneration Programme. Our goal is to permanently address the flooding challenges that have affected the city for many years,” he said.
Nairobi County has also identified 227 flood hotspots across the capital's 17 sub-counties. The areas include locations with blocked or undersized drainage systems, roads requiring desilting and waste removal, vulnerable river corridors and waterways, as well as flood-prone roads and major transport links.
Authorities will also monitor areas where buildings and other structures obstruct water flow, alongside communities considered vulnerable and likely to require early warnings, evacuation, shelter, or relief assistance as the rainy season intensifies.
