Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe. That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here — and boy, have there been some abrupt changes as of late. El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator. Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That’s where we’re at right now. Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer. But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño. Over