September 2026 Monthly Narrative for Northern and Eastern Maine

...SEPTEMBER 2026 CLIMATE NARRATIVE FOR NORTHERN/EASTERN MAINE...

Month Trends:

Caribou:
-​ Mean maximum temperatures were 1.0 degree below average.
-​ Mean minimum temperatures were 2.2 degrees below average. A 
 record low temperature was tied on September 9th, at 34 degrees. 
 It tied with 1946.
-​ Average temperatures were 1.6 degrees below average.
-​ Precipitation was 2.14 inches below average. This is the 5th 
driest September for Caribou on record, with 1.30 inches.
-​ Snowfall was 0.1 inch below average for September. Believe it 
 or not, Caribou typically gets 0.1 inches of snowfall.

Bangor:
-​ Mean maximum temperatures were 0.8 degrees below average.
-​ Mean minimum temperatures were around 0.8 degrees below 
 average.
-​ Average temperatures were around 0.8 degrees below average.
-​ Precipitation was 1.38 inches above average. On September 28th, 
2.17 inches of rainfall fell due to a Nor’easter storm.

Millinocket:
-​ Mean maximum temperatures were 1.2 degrees below average.
-​ Mean minimum temperatures were around normal.
-​ Average temperatures were 0.5 degrees below average.
-​ Precipitation was 1.13 inches below average.

Houlton:
-​ Mean maximum temperatures were 0.8 degrees below average
-​ Mean minimum temperatures were 2.4 degrees below average
-​ Average temperatures were 1.6 degrees below average
-​ Precipitation was 1.81 inches below average. This is the 11th 
 driest September on record for Houlton.

Weather Events:
-​ Frost/freeze program began in May, with northern zones ending 
 in September. The program ended on September 11th in the North 
 Woods. It then ended in eastern/southern Aroostook, 
 northern/central Penobscot, southern Piscataquis, and northern 
 Washington on September 21st. 4 frost advisories were issued in 
 September.
-​ Of the 4 climate sites, Houlton recorded the lowest 
 temperature in September at 28 degrees on the 23rd.
-​ Of the 4 climate sites, Bangor recorded the highest 
 temperature in September at 82 degrees on the 10th.
-​ A significant Nor’easter storm moved through New England at the
 end of September. Interior and coastal Downeast regions got the
 highest rain totals in northern and eastern Maine. Per Caribou 
 Public Information Statement, the highest total recorded by the 
 afternoon of September 28th, was roughly 2.92 inches falling in 
 Milbridge, ME.
-​ The ongoing drought deteriorated throughout September. By
 September 1st, severe drought (D2) was in western Hancock county,
 and up to southern Penobscot. Moderate drought (D1) expanded
 farther north, into most of northern Penobscot, northern
 Piscataquis, and most of Aroostook county. There were pockets of
 abnormally dry (D0) conditions in northern/eastern Aroostook, 
 and parts of southern Washington counties. By September 15th, the
 entire state was, at minimum, in moderate drought (D1). 
 Southern/western Penobscot and Hancock were in severe drought 
 (D2). Far coastal Hancock deteriorated to extreme drought (D3). 
 The state maintained these conditions through the end of the 
 month.

Climate Outlook:
-​ Temperatures: For October, Climate Prediction Center (CPC) 
 does not see strong signals for anomalous temperatures. For the 
 season ahead, the outlook shows temperatures could lean above 
 climatological normal.
-​ Precipitation: For October, CPC does not see strong signals 
 for anomalous precipitation. For the season ahead, outlook also 
 does not see strong signals for anomalous precipitation.
-​ ENSO: Per CPC, El Nino conditions are present, with an El Nino
 Advisory in effect. El Nino has a 90% chance of becoming a very 
 strong event in the northern hemisphere 2026-2027 fall/winter.

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ASB