Weather experts appear divided over when Kenya’s 2026 short rains will begin, with forecasting models yet to agree on their timing and distribution.

🇰🇪 Breaking It Down

The uncertainty comes as Nairobi and several highland areas experience notably chilly conditions, with the country awaiting the October-December rainy season.

Among the experts monitoring the changing weather patterns is Maithya wa Vilivū, who says medium-range models are giving conflicting signals on the onset of the rains.

Maithya attributed the uncertainty to the interaction of a strong El Niño, an emerging positive Indian Ocean Dipole (IOD) and an unclear Madden-Julian Oscillation (MJO) tropical wave.

📌 What You Need to Know

The IOD measures differences in sea temperatures between the western and eastern Indian Ocean, while the MJO is a moving weather system that can influence rainfall and thunderstorms across the tropics.

The interaction of the three patterns can make it harder for forecasting models to determine when and where rainfall will develop.

He noted that successive runs of the European and Global Forecast System (GFS) models since last Friday had produced significant differences in the expected distribution, amounts and consistency of rainfall.

The uncertainty is particularly notable in Nairobi, Central, Western, the Rift Valley and Nyanza, where experts estimate forecast predictability at between 50 and 70 per cent.

However, the greater weather outlook is increasingly pointing towards a wetter season, with models gaining confidence that a positive IOD could develop alongside the strong El Niño.

The latest forecast from the Australian Bureau of Meteorology shows that the positive IOD is likely to strengthen between September and December, reaching its highest point of between +0.8 and +1 degree Celsius in October and November.

📰 Source: Kenyans.co.ke