Jan 2019 – The United States experiences a historic Arctic cold wave, with Chicago plunging to –23 °F, rail tracks warping, schools closing and wind‑chill values below –50 °F, illustrating the severe impacts of a polar‑vortex outbreak [17][25].

July 2025 – A study co‑authored by MIT’s Judah Cohen links increased stretching of the polar vortex to more extreme winter weather in the mid‑latitudes, highlighting the role of Arctic sea‑ice loss in the Barents and Kara seas [9].

Late Nov 2025 – The polar vortex weakens and slides southward, allowing a frigid Arctic air mass to spill into the Plains, Midwest, Great Lakes and Northeast [2].

Dec 1, 2025 – Chicago records the coldest early‑winter temperature since 1876, with forecasts calling for a –14 °F low that matches the 1876 record [8].

Dec 3‑4, 2025 – An Arctic air mass descends across the U.S., affecting roughly 200 million people; Des Moines and Cedar Rapids set daily‑low records of –11 °F and –7 °F, while wind chills reach –10 °F to –25 °F [2].

Dec 8‑14, 2025 – The National Weather Service forecasts a new Arctic blast for the Northeast, with wind chills below zero, potential record lows such as –3 °F in Madison, Wisconsin, and multiple Arctic waves moving through the region [7].

Dec 9, 2025 – Experts warn the upcoming Arctic surge could produce the coldest December temperatures in the Eastern U.S.; a stretched vortex between East Asia and North America is identified as the driver [16].

Dec 12‑14, 2025 – Additional Arctic waves are expected, bringing subzero wind chills across the Northeast and Midwest and prompting a series of cold‑weather advisories [6][7].

Dec 13, 2025 – Extreme‑cold warnings cover North Dakota, West Virginia and Virginia; subzero highs threaten the Upper Midwest, and the USPS alerts to mail‑delivery disruptions in 13 states [5].

Dec 27, 2025 – Two potent cold fronts plunge into the northern U.S. as 2025 ends, flipping the lake‑effect snow machine on, causing >650 flight delays, >600 cancellations, and power outages for >30,000 customers in Michigan; NWS maps show below‑average temps Jan 1‑5 2026 [4].

Jan 5, 2026 – A reconfigured jet stream pushes milder air northward, delivering record warmth to ~240 million Americans, with Texas highs in the mid‑80s and Midwest temperatures 20‑30 °F above normal; the Climate Prediction Center projects this warmth through mid‑January [15][23].

Jan 12, 2026 – A powerful Arctic surge spills into the Midwest and East, first hitting the Great Lakes Tuesday night; a second front arrives early weekend with subzero wind chills, 40 mph gusts, and snow totals exceeding a foot in parts of the Northeast [14][22].

Jan 13, 2026 – Scientists explain that mid‑January is climatologically the coldest period because seasonal lag, snow‑albedo feedback, and a strengthening polar jet stream drive Arctic air southward [13][21].

Jan 15, 2026 – An Arctic blast dominates the forecast for central Ohio, keeping highs in the 20s, wind chills of –5 °F to –15 °F, and prompting a Weather Impact Alert Day and a NWS Cold Weather Advisory [11].

Jan 19, 2026 – The Arctic blast reaches the South, bringing cold rain, freezing rain, ice and occasional snow to Texas, Louisiana, Arkansas and the Southeast; temperatures sit 20‑30 °F below normal, prompting travel warnings and vehicle‑winterization advisories [12][20].

Jan 21, 2026 – A stretched polar vortex, amplified by record‑low Arctic sea‑ice, positions its center near Duluth, Minnesota, projecting minus 25 °F to minus 30 °F for two‑thirds of the U.S.; about 230 million people face 20 °F or colder, with 150 million under snow or ice threats [9].

Jan 22, 2026 – A brutal winter storm forms east of the Rockies as Arctic air collides with warm, moist Gulf flow; experts note that a warming climate does not preclude severe cold and that vortex stretching may have “loaded the dice” for this event [1].

Jan 24, 2026 – NASA satellites capture the storm’s massive cloud shield as it expands from the Plains to cover roughly 50 % of the nation, prompting travel advisories, states of emergency in >12 states, 8,000+ flight cancellations and power‑outage risks for ~140 million people [3].

Jan 28, 2026 – The late‑January storm blankets the U.S. with ice, snow and power outages from New Mexico to New England; a southward‑stretched stratospheric vortex and unusually warm Gulf‑of‑Mexico waters supply abundant moisture, illustrating how climate change can intensify the most extreme winter storms [10][19].

Feb 4, 2026 – A strengthening high‑pressure ridge ushers in nationwide milder air after weeks of Arctic cold, while a lingering trough keeps the Northeast chilly; mid‑February highs are expected 10‑20 °F above average, offering a temporary reprieve for storm‑hit communities [18].