Multiple Factors Have Led to Drought Conditions Across Northern New England

Throughout much of last winter, New England began to creep toward drought conditions as much of the season saw long stretches of cold and dry weather. By the start of 2025, much of New England was in moderate or severe drought conditions. A rather wet spring came along (with a wetter end to winter as well) and eased those drought concerns. This was punctuated by May of 2025, which saw much of New England receive 150 to 200% of normal precipitation for the month.

Even as recently as mid-July, less than 3% of New England was experiencing abnormally dry conditions with only Cape Cod classified as being in a moderate drought. Since then, northern New England has experienced a flash drought amid extremely dry conditions throughout the summer and now into the fall. While both flash droughts and more traditional droughts (obviously) need below average precipitation to develop, more specific atmospheric conditions also need to be present to allow for a flash drought. A flash drought is defined as the rapid onset and intensification of drought conditions.

Below: Current US Drought Monitor:

This flash drought really began to show itself in September. In our last drought update around mid-September, we noted that a large portion of northern New England had been upgraded 2 to 3 drought categories in a six week period from the beginning of August through mid-September. The pace of category change has since slowed down (as expected), but the area experiencing an extreme drought has expanded quite a bit. 51% of northern New England is experiencing an extreme drought. This change is most notable in Vermont, which went from 0% in extreme drought in mid-September to 67% in mid-October.

Below: Current US drought monitor (1st image) versus the US drought monitor from September 11th (2nd image):

This quick-moving drought was spurred not only by low precipitation rates, but also by increased solar radiation from high pressure and sunny days generally dominating and persistently below average humidity over the past couple months. Both of these factors have aided in high evaporation of ground moisture, allowing for the quickly developing drought.

That's been the main issue for much of New England. It's not just the below average precipitation, but also the rapid evaporation of rainfall when it has rained a bit. The Evaporative Demand Drought Index (EDDI) has been very high over the past few months, and has been a significant driver of this drought.

Below: EDDI categories from the past three months:

The rapid evaporation conditions really came to a head as we entered October. Rapid evaporation can occur with sunny days, windy conditions, low humidity, high heat and, of course, a lack of meaningful rainfall. All of these conditions were on full display as we exited September and entered October. This was punctuated by a period of record heat which saw a sustained stretch of 80+° days across New England. This saw the EDDI max out for a majority of northern New England to start off October.

Below: One week EDDI from October 3 to 10:

Another major catalyst for these drought conditions has been the lack of typical humidity over the past few months. As soon as we entered into August, persistent summer humidity went by the wayside. August ended up below average temperature-wise, which also came with a large reduction in humidity. When the air is dry, the ground will also dry out faster as it becomes more difficult to retain moisture. The northeast has seen the lowest relative humidity compared to average conditions in the United States over the past couple months, as seen below.

All of this is punctuated by the continued rainfall deficit across the region, which remains the biggest factor in drought conditions. Fortunately, the pace that the rainfall deficit has increased has now been slowing over the past month or so. Despite this, below average precipitation has continued to persist as of mid-October. Last week's nor'easter certainly helped southern New England's dry conditions with a widespread 1-3+ inches of rain, but northern New England largely missed out, with many areas seeing well under an inch. This has led to well below normal, and in some cases, near record low stream flows.

Below: Seven day average stream flows compared to historic averages:

Going through these impacts, it can be seen that southern New England, while dry, has not seen the kind of extreme conditions line up in the way that northern New England has. This has continued to lead to a contrast between the two areas in drought status. While conditions have rapidly expanded across northern areas, southern areas have been rather stagnant. Looking at the drought comparison from mid-September above, you can see far less change within southern New England. Last week's nor'easter helped improve conditions slightly week or week as well.

Looking at upcoming precipitation chances, things are certainly looking wetter than they have looked in quite some time. Late Sunday and into Monday, a potent cold front with a secondary low will cross the region, likely bringing widespread rain. At this time, a widespread half inch to inch of rain is possible for all of New England out of this system. Afterward, much of next week looks to be unsettled with multiple systems and fronts crossing the region.

Below: Current seven day precipitation outlook: