Kenya braces for El Niño: Heavy rains, possible flooding from October to December

Kenya is entering the second half of 2026 with a strengthening El Niño, the climate pattern linked to unusually warm sea-surface temperatures in the central and eastern tropical Pacific.

The World Meteorological Organization says a strong El Niño is developing and expected to intensify through August–October, while a positive Indian Ocean Dipole (IOD) is also expected to develop.

Together, the two climate drivers could significantly influence rainfall patterns across East Africa.

For Kenya, the immediate concern is not simply that it will rain, but how much, where and for how long.

Kenya expects a wetter-than-normal short-rains season

The latest outlook from the Kenya Meteorological Service Authority forecasts above-average rainfall across about 80 per cent of the country during the October–December 2026 short-rains season.

The rains are expected to be fairly to well distributed in many areas, but the forecast also warns of prolonged wet spells and isolated storms.

Some parts of the country could start receiving the rains as early as September, while the onset in other areas is expected from October.

The strongest signals are around Central Kenya, the Rift Valley, Lake Victoria Basin and Western Kenya, although above-average rainfall is expected across a much wider area.

October to December

The OND season is not just another rainy period.

In parts of Kenya, Ethiopia and Somalia, the short rains can contribute up to 70 per cent of annual rainfall.

Across parts of Uganda, Tanzania, Rwanda and Burundi, they can account for up to 40 per cent.

That makes the forecast important for agriculture, livestock, water supplies and food security.

After months of concern over dry conditions in parts of Kenya, heavier rains could replenish water sources and improve pasture and crop conditions.

But too much rain creates a different set of problems.

Floods and landslides

A wetter-than-normal season does not automatically mean beneficial rainfall.

Prolonged rainfall can overwhelm drainage systems, rivers and dams, particularly where urban development has reduced natural drainage channels.

Heavy storms can also trigger flash floods and landslides, especially in areas with steep terrain or saturated soils.

Nairobi is already preparing for the possibility, with the county government intensifying drainage and flood-mitigation work ahead of the expected rains.

The risk extends beyond the capital.

Roads, bridges, schools, farms and settlements in flood-prone areas can all be affected when rainfall becomes intense or persistent.

What does El Niño actually mean?

El Niño is part of the El Niño-Southern Oscillation (ENSO), a naturally occurring climate pattern involving changes in Pacific Ocean temperatures and atmospheric circulation.

It does not mean that every country experiences the same weather.

The important point for East Africa is that El Niño can shift established rainfall patterns, increasing the likelihood of wetter conditions in some areas while producing drier conditions elsewhere.

That is why an El Niño forecast should not be read as “Kenya will be flooded.”

It is a seasonal probability, not a prediction of exactly what will happen in every county on every day.

What about farmers?

For farmers, the forecast is a mixed bag.

Adequate rainfall could improve soil moisture, pasture and water availability after dry conditions.

But excessive rain can also cause waterlogging, soil erosion, crop damage and delayed harvesting.

The timing matters just as much as the total amount of rain.

A crop can benefit from well-distributed rainfall but suffer if several weeks of rain arrive in a short period.

Kenya's farmers will therefore need to follow county-level and shorter-term forecasts rather than relying solely on the national seasonal outlook.

Could the rains reduce drought?

The latest Kenya Met outlook gives most of the country a low probability of drought during the OND season.

Turkana is an exception, with a 15 - 20 per cent probability of a mild drought event.

Parts of Turkana, Samburu and Marsabit are also expected to have poorer rainfall distribution than many other areas.

So the country could simultaneously face flood risk in some places and dry conditions in others.

Is this another 2023?

ICPAC identifies 1997 and 2023 as relevant analogue years because both experienced wetter-than-normal OND seasons across much of the Greater Horn of Africa.

But the regional climate centre cautions that analogue years are useful for preparedness, not substitutes for the current forecast.

The 2026 forecast should therefore be treated on its own terms.

What should Kenyans watch?

The most important period will be September through December, when the rainfall outlook becomes increasingly relevant to daily conditions.

For households, the practical concerns are flooding, drainage, roads, landslides and water safety.

For farmers, rainfall timing and distribution will matter. For authorities, the challenge is moving from forecasting to preparedness.

And the forecast will continue to change as new observations come in.

El Niño increases the likelihood of certain weather patterns; it does not determine every rainfall event.

The best guide for decisions closer to the ground will be the latest Kenya Met forecasts, advisories and county-level warnings.