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Here’s how El Niño may impact our coming winter

Snow covered mailboxes in Princeton, Mass., earlier this year.Jonathan Wiggs/Globe Staff

Now that we are close to the month of October and have even experienced a few hints of colder weather, there are already many predictions about the upcoming winter. No matter which prediction you look at, nobody really knows what’s going to happen, but there are some variables we can consider in order to help us understand how the atmosphere may unfold in the coming months.

One of the most important, although not the only global indicator, is El Niño. This is part of ENSO, or the El Niño-Southern Oscillation. ENSO represents a relatively predictable pattern of ocean water temperatures oscillating between warmer than average, average, and colder than average.


While the intensity and the frequency of ENSO certainly varies, there is some predictability about how these fluctuations impact global and local weather. You can see this in the images below.

At a very high level these are the most likely although not guaranteed impacts of El Niño during the winter and summer. Note the summer months have much less predictability as to the impact of El Niño.NOAA

Each El Niño is different. The area of Pacific Ocean, where the anomaly of ocean temperatures is measured is vast. As a matter fact, it’s been divided into different regions by scientists. This breakdown of El Niño into smaller components allows us to better understanding how the different types of El Niño will impact weather, especially in the colder months.

Warmer-than-average sea surface temperatures are evident off the coast of Peru this fall.NOAA

The models are pretty clear that El Niño is going to continue to grow and become stronger likely peaking around December. This is common and the reason why the phenomenon was called El Niño in the first place.

El Niño translates to “little boy” in Spanish. Actually the full name, was originally El Niño de Navidad, or the Christ child. Peruvian fisherman named this as they observed a decrease in their December catch as a result of the warmer waters whose intensity often peaked around Christmas.

El Niño is forecast to peak early this winter, but last into spring 2024.NOAA

Our current El Niño comes on the heels of a triple-dip La Niña. That is when ocean temperatures off the coast of Peru are colder than average. Typically you may get one La Niña followed by normal temperatures and then El Niño. It is fairly unusual to have three La Niña’s in a row.


Notice the multiple La Niña, colder than average water just prior to the current El Niño now in place.NOAA

The map below shows the different regions of the Pacific where El Niño and La Niña are measured. Noticed that for this particular El Niño, Regions 1, 2, and 3 are exhibiting the greatest warm anomalies.

There are four major areas of measurement for considering El Niño. All areas currently have an anomaly of at least 1 degree Celsius.NOAA

Because all El Niños are a little bit different, they each impact the global weather patterns much differently. It’s also critical to remember that other oscillations, such as the Pacific Decadal Oscillation or PDO; the Atlantic Multidecadal Oscillation or AMO; as well as shorter oscillations such as the Madden-Julian Oscillation, MJO; Arctic Oscillation, AO; and North Atlantic Osciallion, NAO; are very important.

All have an interplay with each other that determine how seasonal and even shorter-term weather will unfold. The number of variables makes it very difficult to make seasonal forecasts beyond generalities of precipitation and temperature anomalies.

Based on what we know so far, October through December is likely to be warmer than average with near normal precipitation. This doesn’t mean we couldn’t have an early cold snap, some snow, or even a dry or wet stretch, it just means when the three months are put together it will likely have a been a warmer-than-average fall and early winter with adequate precipitation.

The subsequent three months are, of course, the core of winter here. It is still early to predict what might happen in that part of next year, but it is highly unlikely we get away with as little snow and cold as we did last winter.


Forecasters will have a much better idea of what that part of winter might bring later this fall so stay tuned.