September 2025 Monthly Narrative for Northern and Eastern Maine

...September 2025 Climate Narrative for Northern/Eastern Maine...

The September 2025 season wrapped up with above average 
temperatures throughout northern and eastern Maine. Drought 
conditions also continued, and expanded throughout the state, 
with significantly below average precipitation deficits at all 
climate sites.

Temperatures were above normal at all sites, with average mean 
temperatures generally 0.5-1 degrees Fahrenheit above normal. 
Monthly maximum temperatures were significantly above normal by 
2-3 degrees. Houlton was the warmest station, ranging 3.1 degrees
above normal. Millinocket was the next warmest, with max 
temperatures being 2.7 degrees above normal. Lastly, Caribou and 
Bangor both tied 2.1 degrees above climate normals for their 
daytime highs.

Monthly minimum temperatures were generally 0.5-1.5 degrees below
climate normals. Caribou had the largest deviation, being around 
1.5 degrees colder than climate normals. Houlton was next, around
1 degree cooler than normal. Millinocket and Bangor had minor 
deviations, only about 0.3 degrees below average.

Precipitation totals are the main highlight of September, as the 
drought that began in August worsened throughout the month. All 
climate sites underwent continued precipitation deficits. Houlton
had the largest deficit, only receiving 1.67 inches of rain the 
entire month, which is 1.73 inches below normal. This is the 13th 
driest September for Houlton on record, since 1948. Caribou 
received 1.77 inches of precipitation, being 1.67 inches below 
normal for precipitation normals, making it Caribou’s 11th driest 
September since 1939. NWS Caribou observations reported 3.52 
inches of moisture evaporation throughout the month, further 
exacerbating the precipitation deficit. Central Maine did receive 
some wetting rains throughout the month, but none of said storms 
were drought busters. Millinocket received 2.21 inches of rain, 
still resulting in a 1.4 inches deficit. Bangor received the most
rain of all the sites, with a sum of 3.06 inches falling 
throughout the month, resulting in only a 0.70 inch deficit.

In terms of the drought, at the end of August, the North Woods 
region was not under drought. Central and eastern Aroostook, 
alongside northern Piscataquis, Somerset, and Penobscot, were 
abnormally dry. Central Maine and Downeast were in moderate drought,
and coastal Downeast was in severe drought. By September 2nd, 
severe drought expanded up into central Maine, and the interior 
Downeast. By the end of September, abnormally dry conditions 
expanded into the North Woods and remained in northern 
Piscataquis, Penobscot, Somerset and eastern Aroostook. Moderate 
drought conditions were in southern Aroostook, central Piscataquis
and Penobscot. Severe drought extended through central Maine in 
the Penobscot region, interior Downeast, and Washington county’s 
coastal area. Lastly, Hancock county’s coastline upgraded to 
extreme drought conditions by the end of the month.. No 
significant severe weather events occurred in September.

Looking ahead, the Climate Prediction Center (CPC) is anticipating
above average temperatures during October. There are no strong 
signals for above or below average precipitation in Maine. 
Typically, northern and eastern Maine experiences maximum 
temperatures in the 50s, and overnight minimum temperatures in 
the 30s throughout October. Snowfall does typically begin in 
northern and eastern Maine in October, with a climatological 
normal of roughly 0.5-2 inches falling between Caribou and Bangor
by the end of the month.

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ASB