The 2026 El Niño shapes up as one of the strongest on record: what it could mean for snow and the mountains

The equatorial Pacific Ocean is much warmer than normal and the main forecast centres agree: we are in a very strong El Niño that could become one of the most intense on record. Its peak is expected between October 2026 and January 2027, just as the northern hemisphere snow season begins.

What the forecasts say

• The US NOAA declared El Niño conditions on 11 June 2026 and keeps the advisory active.
• In its September discussion, the Climate Prediction Center gave a more than 90% chance of a very strong event this autumn and winter, and a 75% chance that it would be historic in October–December, that is, stronger than any since 1950. In August that probability was 69%.
• October observations compiled by Columbia University’s IRI show temperature anomalies in the east-central Pacific above +3 °C for several weeks in a row.

What El Niño is

It is the warm phase of a natural ocean–atmosphere cycle known as ENSO. When the trade winds weaken, warm water spreads across the equatorial Pacific towards the Americas, altering atmospheric circulation over much of the planet: where it rains, where it is cold and where storms track.

Strong El Niño years also tend to raise the global average temperature. The last big event, in 2023–2024, contributed to the 2024 record, the first year above 1.5 °C.

El Niño is not a weather forecast: it tilts the odds, but every winter has its own story.

And the snow?

The effects vary a lot by region. Some common patterns in strong events:

• North America: it tends to favour more precipitation in the southern United States and the southern Rockies, and milder temperatures in the Pacific Northwest, which can shorten the season at lower elevations in the Cascades.
• South America: heavy rain on the coast of Peru and Ecuador and changes in snow in the central Andes.
• Asia and Oceania: drought in Indonesia and eastern Australia.
• Europe: the signal is weak and unreliable. In the Alps and Pyrenees other patterns, such as the North Atlantic Oscillation, matter far more.

After a disastrous 2025–2026 winter in the western United States —Colorado recorded its worst snowpack, at 22% of the median on 1 April— many resorts are looking to El Niño with hope. But caution is wise: background warming means that, even with plenty of precipitation, the snow line tends to rise.

What to do as a mountaineer

The usual, with even more reason: check the mountain forecast before every outing and do not rely on seasonal outlooks to plan a specific route. If an active front catches you, review how to recognise a storm in the mountains.