Climate experts are eagerly awaiting the declaration of a La Niña, but the global weather pattern is trending weak.

The world has been stuck in a neutral state of the El Niño-Southern Oscillation (ENSO) since early summer, while sea surface anomalies in the region between -0.5°C and 0.5°C over the Pacific Ocean have increased and decreased.

Cooler-than-average waters have been detected by satellites over the central and eastern tropical Pacific in recent months, but they have not yet reached the threshold to declare a La Niña event underway.

ENSO forecast models

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

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

Earlier in 2024, most models indicated that the world would plunge into a La Niña, and a major one. However, fewer and fewer model runs now predict this scenario.

A significant minority of model runs now keep the world in a neutral state for the foreseeable future, impacting extreme weather events during the coming winter and spring.

The latest assessment by NOAA’s Climate Prediction Center on Thursday called for the emergence of La Niña, but forecasters said they expect it to be weak and short-lived.

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

Periods of weaker than usual trade winds over the tropics have caused the Pacific Ocean to warm slightly, slowing the evolution 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.

(The Columbia Climate School, Columbia University)

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

The combination of warming hotspots in the Pacific Ocean and the results of computer models gives forecasters confidence that a significant La Niña is not in the offing in the coming months.

A neutral winter means that El Niño and La Niña conditions are not under control, and generally results in more zonal jet stream patterns. This will lead to fewer extreme cold outbreaks in the northern US and average precipitation levels in the southern part of the country.

A La Niña winter typically results in much colder and snowier conditions across the country, but again, this doesn’t appear to be in the cards for the 2024-2025 season, which begins on December 1.

The 2023-2024 El Niño produced one of the warmest and least snowy winter seasons on record in the US, with temperatures more than 5°F above normal.

Although the coming winter is expected to be somewhat cooler, widespread cold weather records are not expected to be set.

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

The last time the country experienced a cooler-than-average winter was in 2013-2014, when average temperatures were almost a degree below normal.

According to a NOAA database, the coldest winter on record was 1978-1979, with the winters of 1935-1936, 1898-1899, 1909-1910 and 1904-1905 rounding out the top five coldest winters.

This map analyzes the magnitude of warming during 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

Can an El Niño return?

Some forecast models indicate that an El Niño could return in 2025, but here again climate patterns appear to be in no hurry to move to one extreme or the other.

Since reliable ENSO observations began in the 1950s, double El Niño events have occurred only a few times.

Anomalies in ocean water temperature

(NOAA)

The period from 1991 to 1995 was characterized by a double El Niño, with a long stretch of neutral conditions from 1992 to 1994.

A big unknown is the impact of climate change on the behavior of ENSO.

Rising ocean temperatures will likely 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 status.

NOAA provides monthly updates on the status of ENSO, published on the second Thursday of each month.