The “Short Rains” October-November-December (OND) season constitutes an important rainfall season in Kenya, particularly in the Central and Eastern regions of the country.

The Climate Outlook for the October–December 2025 “Short Rains” season indicates that most of the Northeast, Southeastern lowlands and Coastal region are expected to receive below average rainfall.

The South and Central Rift Valley, most of the Lake Victoria region, parts of the Highlands East of the Rift Valley including Nairobi County, some parts over Southeastern lowlands (parts of Kajiado) and western parts of Samburu and Marsabit counties are expected to receive near to below average rainfall.

The Highlands West of the Rift Valley and parts of Northwestern are likely to receive near to above average rainfall.

The main driver of this outlook is the developing negative Indian Ocean Dipole (IOD), which is expected to persist from September to November 2025 before returning to neutral conditions in December. A negative IOD typically brings drier than normal conditions over
East Africa, potentially suppressing rainfall during the short rains.

According to the most recent update issued on 2nd September 2025 by the World Meteorological Organization (WMO), there is about a 55% chance of La Niña developing during September–November 2025, rising to 60% in October–December 2025.

The Kenya Meteorological Department (KMD) will continue to closely monitor ENSO conditions.

The distribution of rainfall is expected to be poor, with prolonged dry spells and isolated storms in some areas.

Detailed Outlook for Particular Regions

The specific outlook for October-November-December (OND) 2025 is as follows:

Highlands West of the Rift Valley

This includes Kisii, Nyamira, Trans Nzoia, Uasin Gishu, West Pokot, Elgeyo Marakwet, Nandi, Kericho, Bomet, Kakamega, Vihiga, Bungoma and the
western parts of Baringo.

The expected rainfall is likely to be near to slightly above the long term average amounts for the season. The distribution of rainfall is likely to be fair to good, with occasional storms expected.

Lake Victoria Basin

This includes Siaya, Kisumu, Homa Bay, Migori and Southern parts of
Busia.

The expected rainfall is likely to be near to slightly below the long-term average amounts for the season except in northern parts of Busia where near to slightly above average rainfall is expected.

The distribution of rainfall is likely to be poor to fair, with occasional storms expected.

Central and South Rift Valley

This brings together Nakuru, Narok and parts of Baringo.

The expected rainfall is likely to be near to slightly below the long-term average amounts for the season.

The distribution of rainfall is likely to be poor to fair, with occasional storms expected.

Turkana County

These areas are likely to receive occasional rainfall that is expected to be near to slightly above the long-term average amounts for the
season. However, prolonged dry spells are likely.

The rainfall is expected to be poorly distributed both spatially and temporally.

Samburu county

These areas are likely to receive occasional rainfall that is expected to be near to slightly below the long-term average amounts for the season
over western Samburu and below average over the rest of the county.

Prolonged dry spells are likely and the rainfall is expected to be poorly distributed both spatially and temporally.

Nairobi and Surrounding Counties

Other counties in this region inlcude Nyeri, Kirinyaga, Murang’a, Kiambu, Meru, Nyandarua, Embu, Tharaka Nithi.

These counties are likely to experience rainfall with some breaks (dry spells) during the season.

The cumulative rainfall amounts are anticipated to be near to below the long-term average for the season in Nairobi, Kiambu, Nyandarua, parts of Murang’a and Nyeri and below average over the remaining parts.

The rainfall distribution is likely to be poor to fair both in time and space with a possibility of occasional storms.

South-eastern Lowlands

Counties in this region incldue Kitui, Makueni, Taita Taveta, Southeastern Kajiado, Tana River and central and eastern Machakos.

These counties are expected to experience intermittent rainfall throughout the season.

However, the total rainfall amounts are likely to be below the long-term average for the season. Prolonged dry spells are also
likely and the rainfall is expected to be poorly distributed both in space and time.

North-Eastern Counties

This includes Mandera, Wajir, Garissa, Isiolo and eastern parts of Marsabit.

These areas are expected to experience occasional rainfall during the season.

However, the total rainfall amounts are likely to be below the long-term average for the season.

Prolonged dry spells are also likely, with the rainfall expected to be poorly distributed both spatially and temporally.

Coastal Counties

This includes Mombasa, Kilifi, Lamu, Kwale and Coastal Tanariver.

These counties are expected to receive rainfall with intermittent breaks during the season.

However, the total amounts are likely to be below the long-term seasonal average.

Prolonged dry spells and occasional storms are also likely, with the rainfall expected to be poorly

Seasonal Rainfall Forecast Distribution

The predicted onsets, cessations, and distribution of rainfall were derived from dynamical models and statistical analysis of the past year, which showed similar characteristics to the current year.

The analogue (similar) year chosen was 2021. The rainfall outcomes for this analogue year are for reference only and should not be interpreted as part of the forecast. Rather, they provide a sense of the rainfall outcomes that can occur given broadly similar global climate
conditions.

OND 2025 rainfall is expected to be poorly distributed, both in time and space over several parts of the country.

The western sector is expected to have a fair to good distribution while the central sector is expected to have a poor to fair distribution. The rest of the country is expected to have a poor distribution.

This season will be marked by prolonged dry spells and occasional isolated storms, even in regions where depressed rainfall (below average) is
forecasted.

Standardized Precipitation Index (SPI) forecast

The SPI forecast for the October–November–December (OND) 2025 season indicates a heightened risk of below-average rainfall across much of Kenya.

The probability of experiencing mild drought conditions (SPI < -0.09) is projected at 55–90% compared to the normal climatological chance of 46%, with the highest risk over the eastern and central regions.

The likelihood of severe drought conditions (SPI < -0.98) is also elevated at 20–55% compared to the usual 16%, particularly in the eastern sector.

These projections suggest that many areas are likely to slide into the mild drought (alert) phase, with a significant possibility of worsening into severe drought (alarm) phase as the season progresses.

Temperature Outlook

The temperature outlook shows that most parts of the country are expected to be warmer than average except a few areas over the western sector where temperature is expected to be near to cooler than average.

The Central and eastern parts of the country are expected to have higher probabilities for warmer than average temperature .

Potential Impacts of the OND 2025 Rains

The expected rainfall during the months of October to December rains season is expected to have both negative and positive impacts across various sectors.

The most likely impacts on various sectors will be highlighted by the sector leads.

There are intraseasonal drivers of variability, such as tropical cyclones and the Madden-Julian Oscillation (MJO), that are only predictable at shorter lead times. It is therefore imperative to stay up to date with subsequent forecasts and updates,” Mugah said.

A photo of a past rainfall season in Nairobi, Kenya. PHOTO/Livenow.