"El Niño" is Coming. What Might That Mean for Minnesota's Weather?

Ocean near-surface water temperature patterns associated with the strong El Niño episode of 1997-98.
Image credit: NOAA Climate Prediction Center.

As 2026 has worn on, Minnesotans have begun hearing a lot about a possible "Super" El Niño developing this fall and winter. What is El Niño and why would a "super" one matter? This article is intended to help readers understand this important global climate pattern, and what it has meant for Minnesota historically. This story updates the version shared before the 2023-24 El Niño.

First, what are El Niño and La Niña?

El Niño is the shorthand name for warmer-than-normal surface and near-surface waters that develop and persist near the equator in the central and eastern Pacific Ocean, generally for periods of nine months or more. This oceanic warming reduces the speed of winds blowing westward across the equator, leading to a large eastward shift in the typical equatorial and tropical thunderstorm activity in the Pacific Ocean. The altered temperature patterns near the surface of the ocean, and resulting changes in the winds in that region, lead to rather substantial changes in many global weather patterns. The additional heat that originates near the equatorial Pacific often ends up distributed far and wide, producing an overall warming effect globally.

La Niña is, effectively, the opposite condition: cooler-than-normal waters develop and persist near the equator in the central and eastern Pacific Ocean, with stronger easterly winds producing a westward shift in equatorial and tropical thunderstorm activity. With cooler waters near the equatorial Pacific, La Niña tends to have a cooling effect globally.

El Niño and La Niña are part of a repeating cycle (though not always a predictable one) that also includes an important neutral phase in which the equatorial Pacific Ocean temperatures remain near normal. The whole phenomenon of regularly "oscillating" water temperature patterns in this part of the Pacific Ocean is termed the "El Niño Southern Oscillation," or ENSO (pronounced "en-so") for short. From 1950 through July 2026, El Niño conditions occurred about 34% of the time, comprising 27 distinct seasonal episodes, each covering the winter season at least (it will be 28 once the 2026-27 episode becomes official). 

(For a much deeper look at ENSO, we recommend the this essay and NOAA's ENSO Blog.)

El Niño and La Niña episodes since 1950
Courtesy: Golden Gate Weather

El Niño Development and Intensity

El Niño tends to develop and intensify during summer or fall and last into early spring. It can develop much earlier in the year, or persist longer, and the record contains instances of back-to-back episodes and continuous El Niño conditions that span parts of three years. 

An El Niño becomes official when ocean temperatures in the  "Niño 3.4 region" remain at least 0.5 degrees C  (0.9 F) above recent 30-year averages for five consecutive three-month periods. An episode is identified as "moderate" if any three-month period is at least 1.0 C (1.8 F) above average, and "strong" if it reaches 1.5 degrees C (2.7 F) above average. NOAA's Climate Prediction Center calls an episode "historically strong" (others use the terms "very strong" or "super") if the Niño 3.4 region is at least 2.0 C (3.6 F) above average.  

Of the 27 El Niño episodes since 1950, six have been moderate, three have been strong, and six have been very strong or historically strong ("super") events. The most recent very strong episode was in 2015-16. The major event in 1982-83 is considered to be the strongest El Niño on record.

El Niño has a reputation as a global climate phenomenon, because it can change the paths and locations of important atmospheric wind patterns, further influencing how weather systems behave and move. The western coasts of Peru and Ecuador, and parts of the southern US, have at times experienced destructively wet conditions during El Niño episodes. Other areas, however, can become much drier than usual. Hurricane and tropical cyclone forecasters often expect less Atlantic activity during El Niño events. Not all areas are affected noticeably by El Niño, but those that are usually see the main effects between fall and spring (spring and fall in the southern hemisphere).

El Niño and Minnesota's Weather

In Minnesota, El Niño conditions have tended to produce mild winters with less snow than average. In fact The 27 El Niño winters since 1950 averaged 2.4 degrees F warmer on a statewide basis than non-El Niño winters, and have produced an average of 24% less snow (13.7 inches) in the Twin Cities. By far the warmest December, and the warmest December-through-February on record in Minnesota, came during the moderate 2023-24 El Niño episode*. The very strong events in1982-83, 1991-92, 1997-98, and  2015-16, and the strong one in1986-87, also are associated with winters that stand among Minnesota's 10 warmest on record. 

Intense winter weather can occur during even major El Niño events. The Halloween Blizzard of 1991 occurred during a very strong El Niño, and was followed by other heavy snowstorms during November, making it the snowiest month on record at many locations. Mild and uneventful conditions did set in during the rest of winter. In 1982-83, the El Niño of record, a mild and wet winter was punctuated by two outstanding blizzards--one in late December and one in mid-April. More recently, the weak El Niño of 2018-19 began with a warm "snow drought" that lasted through mid-January, but then gave way to an incredible winter barrage that included extreme cold and almost endless accumulating snow, which led to spring flooding across the state. The moral of the story is that El Niño tends to yield mild and low-snow winters, but extremely cold and extremely snowy exceptions are always just an Arctic cold front away in Minnesota!

Below are some basic statistics summarizing winter conditions in Minnesota and the Twin Cities during El Niño and non-El Niño years. The transition into and out of El Niño and its overall timing also appear to influence Minnesota's weather. The spring and summer following El Niño events, particularly moderate or stronger, has shown a tendency to be "active," with highly heavy thunderstorms producing an abundance of severe weather and/or rainfall.

*The Climate Prediction Center recently changed the classification scheme it uses to assess the strength of El Niño (and La Niña) events, to account for the ongoing warming of the Pacific Ocean over time. The older index tended to inflate the intensity of more recent episodes while slightly muting historical ones. The newer index attempts to "normalize" the ongoing changes, so that each event is rated relative to what's normal at its time. Thus, the 2023-24 event had appeared to be "very strong" according the old index, but is now technically at the upper end of "moderate" using the new index.    

Winter temperature, precipitation, and snowfall characteristics during El Niño and non- El Niño winters in Minnesota