2020‑2023 – The planet experiences an unprecedented “triple‑dip” La Niña, with three consecutive cool phases that trap warm water at depth, reduce outgoing radiation and intensify the global energy surplus, contributing roughly 23 % of the Earth’s energy imbalance [6].

2022 – Earth’s energy imbalance spikes sharply, and Japanese researchers attribute about three‑quarters of the increase to human‑caused climate change, marking a transition from a multi‑year La Niña cooling to a warming El Niño phase [6].

Early 2023 – Global average monthly temperature shows a noticeable upward jump that persists through 2025, driven by accelerated greenhouse‑gas warming, reduced aerosol pollution, an underwater volcano eruption and modest solar output rise [6].

Winter 2024‑25 (Dec 2024 – Mar 2025) – La Niña re‑establishes across the tropical Pacific, delivering colder, stormier conditions and above‑average snowfall to the northern United States while the South experiences warmer, drier weather and reduced snow, as described by the National Weather Service [2][3].

August 2025 – CNN’s winter‑weather tracker projects above‑average precipitation and temperatures for the northern U.S. this winter, warning that higher temperatures may curb actual snowfall despite abundant moisture [2].

November 2025 – Scientists outline how ENSO phases reshape global weather: El Niño pushes the Pacific jet southward, bringing rain to California and the Gulf Coast, while La Niña shifts the jet northward, delivering wetter, stormier winters to the Pacific Northwest and drier, hotter conditions to the Southwest [8].

December 2025 – The Old Farmer’s Almanac forecasts a milder overall winter for the United States with cold spells in early January, below‑average snowfall in many regions, and a hotter, drier summer, while flagging a late‑June to mid‑August tropical‑storm risk for the Atlantic Corridor [5].

January 9 2026 – The Climate Prediction Center reports a 75 % chance that La Niña will transition to ENSO‑neutral conditions by March 2026 and warns that an atmospheric river will deliver one to three inches of rain, strong winds and snow to Washington, southeastern Alaska and British Columbia over the coming weekend [4].

January 14 2026 – The CPC outlook projects a gradual shift from a weak La Niña to a weak El Niño by the end of summer 2026, which could bring wetter-than‑average winter rains to the Southwest and Gulf Coast while the Northwest, Plains and Midwest remain drier and warmer; drought persists across the southern tier as of mid‑January [7][9].

February 17 2026 – Scientists adopt the Relative Oceanic Niño Index (RONI) to replace the traditional ONI, with NOAA forecaster Michelle L’Heureux saying it “better captures the interactions between the ocean and atmosphere,” and University of Miami researcher Emily Becker noting the old index fell out of sync with impacts because of rapid ocean warming [1].

February 20 2026 – NOAA officially implements a new relative El Niño/La Niña index that can shift event classification by up to 0.5 °C, leading to more La Niña and fewer El Niño detections; Woodwell Climate Research Center scientist Jennifer Francis warns that the higher “normal” heat will fuel more extreme weather worldwide [6].

Late Summer 2026 (forecast) – NOAA projects that an El Niño will develop in late summer 2026, potentially suppressing Atlantic hurricane activity and pushing global temperatures to a new record in 2027 if the event materializes early [6].