Springlike afternoons can disappear fast in March, and the latest forecast is a sharp reminder that warm spells do not always mean winter is finished. Across the eastern half of the country, the recent run of 60s, 70s and even 80s is giving way to colder air, snow chances and another round of temperature whiplash.
The setup is familiar: colder conditions building into the Midwest and Northeast, heavier snow threats near the northern tier, and unusual warmth deepening in parts of the Southwest. That contrast matters because it helps explain why March can feel so unsettled. Meteorologists have described the pattern as a return to the kind of back-and-forth that defined much of winter, with cold air arriving in bursts instead of settling in for one uninterrupted stretch.
Some of that colder push is being linked to the polar vortex, a high-altitude ring of winds that typically traps frigid air near the Arctic. When it stays strong, it helps keep the cold bottled up. When it weakens or shifts, colder air can drop south with a wavier jet stream, according to NOAA’s explanation of the polar vortex. In this case, forecasters have pointed to another disruption that could send fresh waves of chill into the Plains, Great Lakes and East. That does not mean every cold snap has the same cause.
Climate scientists have also noted that the polar vortex is often blamed too broadly. A recent Climate.gov analysis found that some major U.S. cold outbreaks can happen even when the stratospheric vortex remains strong. The takeaway is less dramatic but more useful: cold, snowy weather does not need a single atmospheric villain. Sometimes the larger pattern near the surface is enough to drive a sharp cooldown, especially in late winter and early spring when warm surges and Arctic intrusions can trade places quickly.
For residents in the Upper Midwest and Great Lakes, the immediate concern is snow and travel disruption. Forecasts have highlighted the potential for 6 inches or more in parts of Minnesota, Wisconsin and Michigan, with wind gusts strong enough to cut visibility and make roads dangerous. Farther south, even areas that had started to lean into spring may feel a hard reset, with overnight freezes reaching into parts of the Deep South.
At the same time, the West is dealing with the opposite problem. Parts of the desert Southwest are pushing toward 90 to 100 degrees, and some cities could challenge daily records. That split-screen weather is becoming a defining feature of transitional seasons: one side of the country shedding layers while another side pulls winter coats back out.
The bigger picture is even more complicated. Research summarized by the BBC notes that cold snaps are becoming less frequent and less severe over time, even as individual winter storms can still be intense. The same warming atmosphere that reduces snow in many places can also hold more moisture, which can amplify snow, rain or ice when the temperature profile is right. Between 1949 and 2024, more than 80% of weather stations in the contiguous U.S. recorded a decline in the share of precipitation falling as snow.
So how long will this colder stretch last? The near-term outlook points to some moderation after the next wave of chill, with warmer air trying to push eastward by the middle to latter part of next week. But March rarely offers a clean seasonal handoff. The more realistic expectation is not a final blast or a full thaw, but a few more rounds of winter reminding the East that false spring is still part of the season.
