After an unusually warm fall, the 2025-26 U.S. winter forecast promises a dramatic shift, with La Niña conditions already asserting strong influence. Meteorologists expect widespread below-normal temperatures in December and early January-particularly across the northern and central U.S.-before the pattern begins to ease in late winter. For farmers and ag professionals, this transition will be critical for input deliveries, livestock protection, and soil moisture conditions heading into the 2026 growing season.

According to DTN meteorologist John Baranick, La Niña is expected to peak in December, with Pacific Ocean temperatures well below normal. Global climate models show the atmospheric system weakening by February, potentially shifting toward a neutral or even El Niño pattern by spring. This trajectory aligns with previous winters like 2000 and 2010, which brought severe early-season cold before moderating.

Already, late November is seeing the effects. A clipper system sweeping across the northern Plains is dropping heavy snow and pushing a strong cold front across much of the country. Temperatures are falling rapidly from recent unseasonable highs, and more Arctic air is on the way. A potent weather setup, including upper-level troughs in Canada and the western U.S. and a ridge over Alaska, will funnel additional cold into the lower 48, producing storm activity and possible Great Lakes lake-effect snow.

The first half of December is expected to remain stormy and cold, while the second half may moderate briefly before another round of cold air arrives heading into the new year. While parts of the West and South may see short bursts of chill followed by milder air, northern regions could face prolonged cold, especially if polar vortex disruptions occur. Though currently weaker than usual, the polar vortex may begin to influence U.S. weather again in late December or January, possibly pushing Arctic blasts deep into the interior U.S. and even toward the Gulf Coast.

As for precipitation, La Niña typically creates variable patterns, and that's expected this winter as well. Early in the season, moisture may be more sporadic. But by February, as La Niña weakens, a more consistent storm track is forecast to develop-from Texas through the Ohio Valley to the Northeast-bringing above-normal precipitation to large parts of the Midwest and East. This could offer drought relief in parts of the Corn Belt and improve soil moisture profiles before spring planting.

The Ohio Valley is especially likely to benefit from this moisture-rich setup, while the Western U.S.-particularly coastal states-could see a return to drier-than-normal conditions, potentially worsening drought. Meanwhile, livestock producers in the northern Plains and Great Lakes should brace for higher feed needs and energy costs during what may be an intense first half of winter.

Despite the cold's early dominance, the overall picture becomes more variable as winter progresses. With La Niña fading and the polar vortex's strength uncertain, farmers should expect changing conditions and stay flexible with input purchases, crop plans, and logistics.