Climate experts are eagerly awaiting the declaration of a La Niña, but the global weather pattern tends to be weak.

The world was stuck in a neutral status of El Niño-Southern Oscillation (ENSO) from early summer as sea surface anomalies rose and fell in the region between -0.5°C and 0.5°C over the Pacific.

In recent months, cooler-than-average waters have been detected by satellites over the central and eastern tropical Pacific, but have not reached the threshold to declare an ongoing La Niña event.

ENSO forecast models

(The Columbia Climate School, Columbia University / Vremea FOX)

These conditions have created variable weather patterns around the world – a situation that may persist through much of 2025, according to long-term climate models.

By early 2024, most models indicated that the world would plunge into a La Niña, and a significant one at that. However, fewer and fewer model runs now predict this scenario.

A significant minority of models now keep the world in a neutral status for the foreseeable future, impacting extreme weather conditions during the coming winter and spring.

The the latest assessment from NOAA’s Climate Prediction Center, released Thursday calls for La Niña to emerge soon, but forecasters said it is expected to be weak and short-lived.

“A weak La Niña would be less likely to result in conventional winter effects, although predictable signals could still influence forecast guidance,” CPC forecasters wrote in the update.

Periods of weaker than usual trade winds over the tropics allowed the Pacific to warm slightly, delaying the development of a La Niña event.

WHAT ARE EL NIÑO AND LA NIÑA CLIMATE PATTERNS?

Model comparison showing the evolution of the ENSO forecast from June to October.

(Columbia Climate School, Columbia University)

What are the effects of a neutral winter in the US?

The combination of pockets of Pacific warming and computer model results gives forecasters confidence that a significant La Niña is not in the cards for many months to come.

A neutral winter means that neither El Niño nor La Niña conditions are in control and generally results in more zonal jet stream patterns. This leads to less extreme cold snaps in the northern US and average precipitation levels in the southern part of the country.

A La Niña winter That typically results in much colder and snowier conditions across the country, but again, that doesn’t appear to be in the cards for the 2024-25 season, which begins on December 1.

The 2023-2024 El Niño brought one of the warmest and least snowy winters on record worldwide. USwith temperatures over 5°F above normal.

Although next winter is expected to be somewhat cooler, it is not anticipated to set any widespread cold weather records.

The combination of the ENSO condition and general climate warming is expected to keep temperatures above average across much of the country.

The last time the country experienced a colder than average winter was in 2013–14, when the average temperature was almost a degree below typical values.

According to a NOAA database, the coldest winter on record was 1978–79, with the winters of 1935–36, 1898–1899, 1909–10, and 1904–05 rounding out the top five coldest winters.

This map analyzes the magnitude of warming in the winter months (December-February) using 52 years of temperature data (1970-2021).

(Map: Climate Central; Data: NOAA/NCEI/NOAA)

LITTLE KNOWN WEATHER PATTERN WHEN EL NIÑO AND LA NIÑA ARE NO LONGER UNDER CONTROL

Could an El Niño return?

Some forecast models indicate that year El Nino it could return in 2025, but again, climate models don’t seem to be in a rush to venture to one extreme or the other.

Since reliable observations of ENSO began in the 1950s, there have been only a few occasions when a double El Niño has formed.

Ocean water temperature anomalies

(NOAA)

The period from 1991 to 1995 was marked by a double El Niño, with an extended run of neutral conditions from 1992 to 1994.

A major unknown is impact climate modification of ENSO behavior.

Rising ocean temperatures are likely to increase the frequency of El Niño events, but more research is needed to understand how warmer seas will influence changes in the world’s ENSO state.

NOAA provides monthly updates on the state of ENSO, released on the second Thursday of each month.