The Kenya Meteorological Department has issued a heavy rainfall advisory warning residents in over 28 counties to brace for possible flash floods, strong winds, and lightning strikes between Sunday, August 17, and Tuesday, August 19, 2025.

According to the advisory released on Friday, August 15, the rainfall currently affecting parts of the Lake Victoria Basin, the Rift Valley, and the Highlands west of the Rift Valley is expected to intensify to more than 20 mm in 24 hours.

The rains will spread to the Highlands east of the Rift Valley, including Nairobi, on Sunday, before gradually reducing in intensity from Wednesday, August 20.

“The rainfall pounding parts of the Lake Victoria Basin, the Rift Valley and the Highlands West of the Rift Valley is expected to intensify to more than 20 mm in 24 hrs and spread to the Highlands East of Rift Valley on Sunday,17th August, 2025. The heavy rainfall is likely to continue up to Tuesday, 19th August, 2025. It is projected to reduce in intensity from Wednesday, 20th August, 2025,” the advisory read in part.

Counties to be affected

The counties expected to be affected include Kisumu, Homa Bay, Siaya, Migori, Busia, Kisii, Nyamira, Nandi, Kericho, Bomet, Kakamega, Vihiga, Bungoma, Narok, Baringo, Nakuru, Trans Nzoia, Uasin Gishu, Elgeyo Marakwet, West Pokot, Turkana, Samburu, Marsabit, Nyandarua, Laikipia, Nyeri, Kirinyaga, Nairobi, and parts of Murang’a, Kiambu, Meru, Embu, and Tharaka Nithi.

“YELLOW WARNING. Heavy Rainfall Advisory, 17–19 Aug 2025: Rain >20mm/24hrs to pound Lake Victoria Basin, Rift Valley & Highlands W. Rift, spreading to Highlands E. Rift on 17th. Heavy rains ease from 20th. Strong winds >25knots in eastern sector to persist. Risk of flash floods, poor visibility, strong winds & lightning. Avoid walking/driving in moving water & sheltering under trees. Stay informed & prepared,” the weatherman warned.

Strong winds

The Met Department further warned that strong southerly winds exceeding 25 knots (12.9 m/s) in the eastern sector could cause damage to structures, uproot trees, and blow off roofs.

Residents are advised to avoid walking or driving through moving water, staying in open fields, or sheltering under trees and near grilled windows to minimise lightning risks.