Drought Is Fading in the Northeastern United States as Rising Rainfall Wins Out

While much of the American West has become a poster child for intensifying drought under climate change, the northeastern corner of the country has quietly been moving in the opposite direction. A new study from Dartmouth College, published in the Journal of Hydrometeorology, reports that over the past century droughts across the Northeast have become both less frequent and less intense, thanks to increasing precipitation that has more than compensated for the extra water the atmosphere pulls from soils and plants as temperatures climb. The finding offers a nuanced picture of how a warming climate can produce starkly divergent water-cycle outcomes across regions, and it challenges assumptions that all parts of the United States are sliding uniformly toward drier conditions.

The physics behind drought under climate change is a contest between two opposing forces. As the Earth warms, there is more energy available to evaporate water from vegetation and soil, a process scientists call evapotranspiration. If rainfall does not increase to cover that rising water loss, deficits accumulate and drought intensifies. In many arid regions, particularly the West, that is exactly what has happened. But in the Northeast, according to lead author Jonathan Winter, an associate professor of geography at Dartmouth and director of the Dartmouth Applied Hydroclimatology Group, both sides of the ledger have been growing. Warming temperatures are draining more moisture from the land surface, yet precipitation has been increasing at a rate that has so far outpaced the loss.

Winter describes the dynamic as a tug-of-war between how fast precipitation is increasing and how fast evapotranspiration—the loss of water from plants and soils—is accelerating. In the Northeast, precipitation has been winning. His team’s prior work has documented striking increases in extreme precipitation across the region, and the new analysis extends that picture by showing that the extra rainfall is not merely producing isolated downpours. It has fundamentally shifted the long-term drought climatology of a twelve-state region that includes Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and West Virginia, along with Washington, D.C.

To quantify the change, the researchers examined monthly drought conditions from 1901 to 2022 using temperature and precipitation station data from the National Oceanic and Atmospheric Administration. Rather than relying on a single metric, the team assessed drought across four dimensions: intensity, frequency, variance, and duration. Drawing on temperature, precipitation, radiation, and soil data, they calculated the Palmer Drought Severity Index, a widely used measure that integrates water supply and atmospheric demand into a single drought score. They then compared their results against the U.S. Drought Monitor, the weekly map of drought conditions that carries real-world financial weight because it is used to determine payouts for crop insurance.

Because direct soil moisture measurements across the Northeast are limited, the researchers also used modeled soil moisture, which blends output from a climate model with observational data, to check whether the changes seen in atmospheric drought indices were mirrored in the water actually held in the ground. The multiple lines of evidence converged on the same conclusion. Across all months of the year, drought was 59 percent less frequent and 19 percent less intense from 1984 to 2022 compared with the period from 1901 to 1983. In the warm season from June through November, when drought delivers its largest blows to agriculture and water supplies, the changes were nearly identical: frequency fell by 56 percent and intensity by 16 percent.

The results also indicate that as of 1984, the Northeast became statistically wetter relative to the previous eight decades, marking an apparent regime shift in the region’s hydroclimate. Notably, the analysis found that swings between monthly wet and dry events have not changed, which means the region has not experienced more of the so-called weather whiplash—the jarring alternation between floods and droughts that has been documented in some other parts of the world. The Northeast is not lurching more violently between extremes; it has simply spent far less time in the dry half of the spectrum since the mid-1980s.

To identify the driver behind the drought decline, the researchers designed an attribution exercise. They reran their analysis twice, first holding temperature at historic levels while allowing precipitation to increase, and then reversing the setup, letting temperatures rise while pinning precipitation down. The outcome was unambiguous: precipitation increases are responsible for the observed reductions in drought. In other words, the extra rain the region has been receiving is not a coincidence of natural variability riding on top of warming; it is the mechanism that has kept the drought ledger in the black for nearly four decades, overcoming the growing atmospheric demand that warmer air imposes.

That mechanism’s future, however, is far from certain. As long as increases in precipitation continue to outpace increases in evapotranspiration, more drought in the Northeast is unlikely, Winter notes. But climate models disagree on whether the region’s precipitation will keep rising at the pace needed to stay ahead of warming-driven water losses. If evapotranspiration accelerates faster than rainfall, the tug-of-war could tip the other way, and the drought protection the Northeast has enjoyed could erode. The study does not predict the end of drought, only its recent decline—and even that decline is relative to a historical baseline that included some devastating dry spells.

Co-author Erich Osterberg, a professor of Earth and planetary sciences at Dartmouth, emphasizes that droughts remain a live threat. A year ago, more than one-third of the Northeast was in severe or extreme drought, with major impacts on farmers and water supplies. The good news, he says, is that these damaging droughts have become less common and less severe because of more rainfall. The bad news is that the higher rainfall has increased the frequency and impacts of severe floods. The region’s changing water cycle is not a free lunch: water that rescues crops during dry summers can also inundate communities during wet ones, and the same precipitation surplus that suppresses drought can amplify flood risk when it arrives in concentrated bursts.

The researchers hope their findings will inform climate change adaptation and water management decisions across the Northeast. For reservoir operators, agricultural agencies, and insurers who depend on tools like the U.S. Drought Monitor, understanding that the region’s drought baseline has shifted—and knowing why—can sharpen planning for both the lingering dry extremes and the growing wet ones. Janelle Wargo, Guarini ’25, and Justin Mankin, a professor of geography at Dartmouth, also contributed to the study. As the broader American climate story continues to be dominated by drought in the Southwest and fire seasons in the West, the Northeast’s wetter trajectory stands as a reminder that climate change is not a single story but a patchwork of regional contests between water arriving from the sky and water leaving the land.

Subject of Research: Long-term changes in drought frequency and intensity across the northeastern United States driven by increasing precipitation.

Article Title: Drought in the Northeastern United States has decreased

Article References: Drought in the Northeastern United States has decreased. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: drought, Northeastern United States, climate change, precipitation, evapotranspiration, Palmer Drought Severity Index, soil moisture, U.S. Drought Monitor, water management, hydroclimate, weather whiplash, Dartmouth College