Our planet may soon experience a new annual temperature record due to the natural climate phenomenon El Niño, which current forecasts indicate will develop in the second half of 2026 and could become very strong late in the year. El Niño phases influence weather extremes around the world – and tend to be accompanied by higher temperatures.

Depending on the strength of a given El Niño phase, further increases in temperature are conceivable on top of the rising temperatures caused by climate change. The hottest year in terms of global mean temperature so far was 2024, at around 1.5°C above the average for the pre-industrial period (1850–1900). In fact, 2024 was affected by an El Niño phase that had begun in 2023, mirroring the current situation. According to forecasting models, while it is likely that 2027 will set a new temperature record, it is not a certainly.

El Niño is a phenomenon caused by the El Niño-Southern Oscillation (ENSO), a periodic fluctuation in Pacific Ocean surface temperatures. In its neutral state, surface water in the western Pacific is much warmer than in the eastern Pacific off the coast of South America. During La Niña phases, the difference in temperature is even greater. In contrast, during El Niño phases, weakened trade winds transport lower quantities of warm surface water westward. As a result, the waters off the coast of South America warm up, while the western Pacific cools. The term “Super El Niño” is used when the surface water in a specific region of the Pacific (Niño 3.4 anomaly) is more than 2°C warmer than the long-term average.

Generally speaking, the effects are reversed in La Niña years. In other words, they result in more tropical cyclones in the North Atlantic and more frequent floods in eastern Australia. Exact predictions are always difficult in such circumstances, because other cyclical oscillations also play a role.

Alternating El Niño and La Niña phases typically last one or two years – with La Niña phases normally lasting somewhat longer in comparison. For roughly the past two years, La Niña or at least neutral conditions have prevailed. Many experts are now expecting a very strong El Niño for the second half of the year, which could match or even exceed the most intense El Niño of recent years, from 2016.

ENSO fluctuations affect not just local weather phenomena, but also global mean temperatures: El Niño increases them, while La Niña reduces them slightly. It is worth noting that the last 12 years have been the warmest since records began. Influenced by an El Niño phase that had started in 2023, the hottest year on record is 2024, when the mean temperature was almost 1.5°C above the pre-industrial average. But the recent hot years have also been interspersed with several neutral and La Niña years, e.g. in 2020–2022 and 2025. As this shows: the effects of natural climate cycles are overlapping with those of climate change, producing a trend toward higher temperatures.

However, there is no scientific consensus yet as to whether climate change is having a direct impact on ENSO fluctuations. Some studies indicate that climate change is also intensifying the ENSO phases themselves – in the same way that it is worsening the extremes of many natural hazards.

The pronounced effects of cyclical climate fluctuations – in combination with the effects of climate change itself – illustrate how important research in this area and the insights gained from it are, not least for insurers. Using historical statistics alone for risk management is not enough. Instead, fluctuations from natural climate cycles need to be considered, and the long-term effects of climate change precisely mapped in the risk strategy.

There are dozens of scientists at Munich Re – from meteorologists and hydrologists to climate scientists – all working on risk models and risk assessments that make it possible for us to cover disaster risks on a large scale. Doing so is of fundamental importance: insurers assume a portion of the financial losses incurred by disaster victims – enabling them to return to their normal lives as quickly as possible.