As El Nino conditions develop in the Pacific Ocean, Kenyan meteorologists caution against assuming it will inevitably lead to severe flooding across the country. The Kenya Meteorological Services Authority (KMSA) emphasizes that El Nino is just one factor influencing weather patterns, with the Indian Ocean Dipole (IOD) playing a critical role in East Africa’s rainfall outcomes.

Understanding El Nino and Its Impact

Hannah Kimani, Assistant Director of Public Weather Services at KMSA, explains that El Nino is a natural climate phenomenon characterized by warmer sea surface temperatures in the central and eastern Pacific Ocean. It is part of the El Nino Southern Oscillation cycle, which also includes the neutral phase and La Nina, the cool phase.

Despite originating thousands of kilometers away, El Nino affects global weather due to interconnected ocean-atmosphere systems. However, in East Africa, the IOD’s state largely determines whether El Nino’s presence translates into increased rainfall.

The Role of the Indian Ocean Dipole

The IOD involves variations in sea surface temperatures between the western and eastern Indian Ocean. A positive IOD, characterized by warmer waters near East Africa and cooler waters near Australia, tends to enhance rainfall over Kenya and neighboring regions.

Kimani notes that El Nino itself is not rainfall but a climate driver that influences temperature and precipitation patterns. The intensity of rainfall depends on how El Nino interacts with the IOD.

Historical examples illustrate this relationship:

  • In 2015, a very strong El Nino occurred, but Kenya experienced only moderate rainfall due to a weak positive IOD.
  • The 1997-98 and 2023 El Nino events coincided with strong positive IODs, leading to widespread flooding.
  • In 2019, Kenya saw heavy rainfall and flooding triggered by the strongest recorded positive IOD, despite no major El Nino event.

Current Conditions and Preparedness

The 2026 El Nino is already influencing Kenya’s weather, contributing to warmer temperatures in Nairobi, central Kenya, and parts of western Kenya during typically cooler months. It has also caused below-average rainfall in western Kenya and the North Rift from June to September.

Forecasts indicate an 81% chance of the El Nino strengthening to a very strong event later this year, along with over a 90% probability of a positive IOD developing. Meteorologists continue to monitor these evolving conditions closely.

Rather than inciting alarm, Kimani urges Kenyans to use these forecasts to prepare effectively. Benefits of above-average rainfall include improved hydropower generation, enhanced soil moisture for agriculture, and opportunities for rainwater harvesting.

She calls for coordinated efforts between national and county governments to promote climate-smart agriculture, upgrade drainage infrastructure, and strengthen early warning systems. At the individual level, she recommends proactive measures such as investing in water tanks to harvest rainwater, which remain valuable regardless of rainfall variability.

The Kenya Meteorological Services Authority plans to hold the National Climate Outlook Forum soon, gathering experts from multiple sectors to refine seasonal forecasts and issue targeted advisories ahead of the October-December short rains.

Kimani concludes, "The focus should be on understanding El Nino’s implications, monitoring the Indian Ocean Dipole, and taking early action to mitigate risks while maximizing the benefits of favorable rainfall."