When we talk about Dallas/Fort Worth’s coldest mornings, the official record low of −8°F in February 1899 usually takes center stage. But the thermometer record only began in 1898. That means some of the most brutal Arctic outbreaks in Texas history — the ones that froze the Mississippi River at New Orleans — happened before we had instruments in place to capture them. By piecing together proxy evidence and ocean cycle timing, we can reconstruct a hidden history of subzero mornings in North Texas.

The AMO Cycle and Cold Outbreaks

The Atlantic Multidecadal Oscillation (AMO) is a natural climate variability pattern characterized by long-duration changes in the sea surface temperature of the North Atlantic Ocean. The AMO flips between warm and cold phases every 25–40 years. These transitions often coincide with instability in jet stream patterns, opening the door for Arctic air to plunge south. United States winters are colder during the cold phase of the AMO.

• Warm AMO: Fewer outbreaks, but sharp extremes still possible (1989, 2021).
• Cold AMO: More frequent and deeper outbreaks (1835, 1887, 1899).
• Phase flips: The most punishing cold often clusters right before or during a transition.

Mississippi River Freezes at New Orleans

Freezing the Mississippi at New Orleans is the ultimate proxy signal. It means the Arctic dome was so deep that even the Gulf Coast was locked below freezing for days. The last time the Mississippi River froze at New Orleans was in February of 1899, and DFW’s temperature reached -8°F. So if the cold was severe enough to freeze the Mississippi River at New Orleans, then we can reasonably project that the temperature in DFW was at least -5°F to -8°F, but likely colder than -8°F, especially the earlier you go back given the “Little Ice Age” effect on temperatures.

• January 1785: Post‑Laki eruption winter. Mississippi froze, implying DFW likely hit −8°F or colder.
• January 1816: Tambora eruption, “Year Without a Summer.” Gulf freezes suggest another subzero event in DFW.
• January 1835: The “Cold Friday” outbreak destroyed citrus groves and froze the Mississippi. DFW likely plunged to −8°F to −12°F.
• January 1887: The “Great Die‑Up” winter. Ranchers reported weeks of continuous freezing weather. Mississippi froze again, pointing to subzero in DFW.
• February 1899: The benchmark. New Orleans hit 3°F, Galveston 0°F, and Dallas officially recorded −8°F.

Reconstructed + Documented Subzero Timeline for DFW

Here’s the likely history of DFW’s coldest mornings, reconstructed before records and documented after 1899, aligned with AMO phasing:

The Pattern

Year	Event	Mississippi River	DFW Minimum	AMO Context
1785	Post‑Laki Eruption	Froze at New Orleans	−10°F to −12°F (reconstructed)	Transition to cool phase
1816	Tambora Eruption	Froze at New Orleans	−10°F or colder (reconstructed)	Transition to cool phase
1835	Cold Friday Outbreak	Froze at New Orleans	−10°F to −12°F (reconstructed)	Transition toward warm phase
1857*	Severe Arctic Outbreak	Anecdotal Gulf Freezes (Not reliable)	Possible subzero cold in DFW (reconstructed)	Cold AMO Phase flipping to Warm
1864*	Civil War Outbreak	Many reports of Frozen Rivers	Possible subzero cold in DFW (reconstructed)	Warm Phase AMO
1887	Great Die‑Up Winter	Froze at New Orleans	−8°F to −10°F (reconstructed)	End of warm phase, volcanic forcing
1899	Great Arctic Outbreak	Froze at New Orleans	−8°F (official record)	Flip into cool phase
1930	Jan Arctic Outbreak	No freeze	-1°F at DFW	Transition toward warm phase
1949	Jan Arctic Outbreak	No freeze	-2°F at DFW	End of warm phase, flip to cool
1989	Dec Arctic Outbreak	No freeze	−1°F at DFW	End of cool phase, flip to warm
2021	Feb Arctic Outbreak	No freeze	−2°F at DFW	End of warm phase, flip to cool

• Every documented subzero event in DFW clusters near an AMO phase flip.
• Pre‑1899: Gulf freezes are the proxy “smoking gun” for subzero.
• Post‑1899: Instrument records confirm the same rhythm — 1930, 1949, 1989, 2021 all arrived near AMO transitions.
• Volcanic outliers (1816, 1887): Amplified the cold beyond the cycle, but still fit the broader timing.

Summary

Dallas/Fort Worth’s official record low of −8°F in 1899 is only part of the story. Proxy evidence from Mississippi River freezes shows that DFW likely fell below zero multiple times before records began, maybe as cold as -10°F to -15°F — in 1785, 1816, 1835, and 1887. And history shows that every subzero event has clustered around AMO phase flips. The next AMO flip may be coming soon!

November 2025 has been nothing short of historic in Dallas/Fort Worth. Temperatures have soared to very warm levels, cementing it as the hottest November on record thus far. Several daily temperature records have been broken. But if history is any guide, this kind of extreme warmth rarely lasts. In fact, some of the hottest Novembers in DFW history have been followed by some of the coldest Decembers.

Lessons from the Past

• 1909: Severely cold December that followed a very warm November. Also a La Niña winter with similar setup to 2025.
• 1917: Very cold December that was also a La Niña winter that has similar setup to this year that followed a warm November.
• 1963: November was unusually warm, but December flipped dramatically. Arctic outbreaks brought extended freezes and snow events across Texas.
• 1983: A warm November gave way to the coldest December ever recorded in DFW. The city endured 295 consecutive hours below freezing, with temperatures averaging nearly 12°F below normal.
• 1989: A textbook flip—November ran above normal, but December plunged to -9.1°F, delivering DFW’s third coldest temperature on record at -1°F on December 23.
• 2000: Another warm November preceded the third coldest December on record. Arctic air dominated, and snow fell across much of Texas.

Why the Flip Happens

The atmosphere often seeks balance after extreme anomalies. When November runs hot, December can swing the other way — especially when the large‑scale teleconnections line up. Right now, they do:

Key Current Teleconnection Signals (Late November 2025)

• Negative PNA: Western troughing favors downstream ridging into the Southeast, opening the door for cold delivery into the Plains.
• Negative WPO/EPO: High-latitude blocking near Alaska and the Bering Sea reinforces Arctic air displacement.
• Negative NAO/AO: Greenland blocking and polar pressure anomalies support meridional flow and cold intrusions.
• MJO Phases 7–8–1: Tropical forcing is entering cold-favorable phases, historically linked to high-latitude blocking and U.S. cold outbreaks 10–20 days later.
• Stratospheric Warming: A major SSW event is unfolding unusually early, disrupting the polar vortex and increasing the risk of Arctic air spilling southward.

What It Means for December 2025

With November 2025 running hottest on record, the analogs and current teleconnections strongly suggest a high risk of a cold flip. The setup resembles 1963, 1983, and 2000 — years when Texas endured some of its most memorable Arctic outbreaks. December may not be a wall‑to‑wall freeze, but the risk of sharp cold shots is elevated. Expect volatility: warm interludes punctuated by strong Arctic fronts, especially mid-to-late month.

Bottom line: November’s record heat is not sustainable. With the NAO, PNA, WPO, AO, and EPO all trending negative, the Arctic door is opening. History tells us that when DFW runs hottest in November, December can deliver some very cold air. Winter 2025–26 may be setting up to follow that script. Time will tell if the cold comes and if it lasts into much of the winter or retreats. Keep in mind that this is not a forecast, just something that we are monitoring.