What a very strong El Nino means

This is the strongest seasonal signal in the atmosphere, and it is the reason every forecaster is talking about the coming winter. It is also routinely oversold. Here is what it actually buys you.

Source: NOAA Climate Prediction Center, Prognostic Discussion for Long-Lead Seasonal Outlooks, issued 16 July 2026.

Where things stand

NOAA has an El Nino Advisory in effect: El Nino is present, sea surface temperatures are above average across the central and eastern Pacific, and the atmosphere is responding the way it does in an El Nino year.

The latest departures CPC reports run +2.6 C in the far eastern Pacific (the Nino 1+2 region), +1.7 C in Nino 3, and +1.3 C in Nino 3.4, the region most used to classify events. CPC gives an 81% chance the event is very strong through October to December, falling to 75% through November to January, and a 97% chance El Nino of some strength lasts into early spring 2027.

What it tilts

El Nino warms the tropical Pacific, which shifts where thunderstorms cluster, which moves the jet streams that steer North American weather. The subtropical jet strengthens and runs further north, and the winter pattern that follows is consistent enough to be useful:

• Wetter across the southern tier. CPC puts the highest above-normal winter precipitation probabilities in the country over parts of the Southeast, where it says the teleconnections are strongest.
• Drier from the Northwest into the Central Plains. The northern storm track tends to be starved as the southern one is fed.
• Milder across the north. By winter, CPC's temperature pattern is dominated by above-normal probabilities over the west, north and east rather than the southern tier.
• Near-normal, not cold, in parts of the south. CPC indicates near-normal temperature chances over parts of the Southwest, the Southeast and the Lower Mississippi Valley, where a wetter, cloudier pattern offsets the long-run warming trend.

What it does not do

This is the part that gets lost between the forecast and the headline.

• It shifts odds. It does not schedule weather. A favoured category at 40% means the other two still hold 60% between them.
• Strong signal does not mean strong certainty. A very strong El Nino makes the seasonal tilt more reliable. It says nothing about any particular week.
• Seasonal averages hide the events that hurt. A winter can finish milder than normal and still deliver the ice storm, the cold snap, or the roof-loading snowfall. Plan for the extreme, not the average.
• No two El Ninos are the same. Other patterns run at the same time, and they can reinforce or cancel the signal regionally. CPC marks the places where the signals fight as equal chances rather than guessing.

So what should you actually do

Read the odds for your own region, then plan against your own normals rather than the national story. A mild-leaning winter in the Upper Midwest is still an Upper Midwest winter.

• Your regional outlook, with the numbers next to your station's normals.
• Your frost dates, which are normals and do not move with the seasonal forecast.
• Firewood and winter hay supply, both of which are sized off a normal season plus a margin, not off a forecast.

For how every other number on this site is computed and sourced, see the methodology.