MILWAUKEE - October just wrapped up, and it was the 6th warmest October in Milwaukee. Approximately 71% of the month had warmer than average temperatures with the warmest day and a record high of 87°F set on Oct. 12.
Warmer temperatures this fall will likely be followed by warmer temperatures this winter as El Niño is already here.
The term El Niño has been tossed around over the years, but what is it?
El Niño explainer
Dig deeper:
During a normal year near the equator in the equatorial Pacific, trade winds, which blow east to west, push warm surface waters towards Asia. Cool water then upwells where the warm water was.
During an El Niño year, the trade winds are weaker, causing the warm water to sit in place rather than moving east and causing less cool water to upwell near the surface.
Warmer waters intensify and shift the jet stream south, causing a shift in weather during the winter months, primarily in North America.
A typical El Niño winter causes wetter conditions and potential flooding in the southern United States, warmer temperatures from the Pacific Northwest into the Midwest, and drier conditions near the Ohio River Valley.
2026-2027 winter outlook
Across the nation:
The 2026 to 2027 winter forecast for December, January, and February looks consistent with what a normal El Niño would bring: warmer temperatures for the northern half of the country and wetter weather for the southern half.
Initial NOAA forecast to current
Big picture view:
At the beginning of October, NOAA noted that El Niño will continue to strengthen through the end of the year.
There is an 83% chance that a strong to very strong El Niño develops through the winter, which could be historic compared to previous El Niño events. On Nov. 2, NOAA released an update that El Niño is here.
Sea surface temperatures are above average across the east-central and eastern Pacific Ocean. There is an 83% chance that it continues to strengthen into the winter and early spring.
It could potentially be one of the strongest El Niños on record. The previous very strong El Niños occurred in: 1982-1983, 1997-1998, and 2015-2016.
How do we know if the waters are warmer or colder?
What we know:
The National Weather Service Climate Prediction Center has data showing a 3-month rolling mean of sea surface temperature anomalies not only in the equatorial Pacific Ocean, but the global tropics.
Meteorologists analyze this data and more to determine what is going on in the ocean which is connected to the atmosphere to forecast future weather.
What does this mean for Wisconsin?
Local View:
Locally, El Niño brings warmer than average temperatures in the winter and early spring. In fact, 100% of the time a strong El Niño has been present, Milwaukee experienced 70°F and 80°F temperatures in March.
During these past very strong El Niños, Milwaukee ranked in the top 15 warmest winters on record!
Based on the 1991-2020 normal climate period, Milwaukee averages 48.7" of snowfall per year with 37.1" accumulating in winter from December through February.
Historically, in years when there has been a strong or very strong El Niño, Milwaukee only receives nearly half the normal amount of snowfall.
This doesn’t mean that Milwaukee can’t experience cold days or even snow, but warmer temperatures can impact systems that bring precipitation, making it fall more as rain or a wintry mix.
Wisconsin winter impacts
Why you should care:
Evidence shows that warmer temperatures in winter and early spring cause the first buds of plants to arrive earlier in the year. This leads to longer periods of freeze-free days, which lengthens the duration plants can grow.
The elongated growing season means that plants are blooming earlier and hibernating later, leading to a longer allergy season. So, with a very strong El Niño forecasted for this year, anticipate tree allergy season to be heightened, and more money spent out of your pocket to get relief from it.
If you enjoy winter recreation outdoors, expect that to be limited. With the lack of snow forecast, sledding, snowmobiling, snowshoeing, and ice fishing will be limited. The economy from snow plowing will likely be impacted due to less snow. You will need to take advantage of it when we get it.
The good news is that El Niño doesn't last forever, and there will still be cooler winters with more snow in the future.
The Source: Information in this story is from the National Oceanic and Atmospheric Administration, Climate Prediction Center, and the FOX6 Weather Experts.