2024 Annual Climate Summary for Northern and Eastern Maine

...2024 ANNUAL CLIMATE REVIEW FOR NORTHERN AND EASTERN MAINE...

2024 was a very warm year across northern and eastern Maine. In
Caribou, it was the warmest year since weather records began in
1939. The average annual temperature of 44.7F established a new
record surpassing 2010 when the average temperature for the year was
44.4F.

In Houlton, it was the 2nd warmest year on record with an average
temperature of 44.0F. The all-time warmest year on record is still
2010 when the average annual temperature was 44.1F. Weather records
in Houlton began in 1948.

In Millinocket, which has a very long period of weather records
dating back to 1903, it was the warmest year on record with an
average annual temperature of 46.4F. This broke the previous record
of 45.6F, set in 2012.

In Bangor, it was the 2nd warmest year on record. Weather records in
Bangor began in December 1925. The average annual temperature of
47.8F fell just shy of the all-time warmest year which remains 2010
when the average annual temperature was 48.2F.

Precipitation in Caribou was below average with a total of 34.89
inches of rain (and melted snow). This was 5.81 inches below the
1991-2020 average. It ranked as the 23rd driest year on record. A
total of 90.5 inches of snow was observed, which made it the 13th
least snowy year on record.

Precipitation in Bangor was very close to the 1991-2020 average. A
total of 41.79 inches of rain (and melted snow) was observed, which
was just 0.07" above average. A total of 52.6 inches of snow was
observed, which made it the 16th least snowy year on record.

January featured temperatures that ranged from 3.5 to 5 degrees (F)
above average. Precipitation was mostly below average, except a bit
above average along the coast. Snowfall was near normal. The most
significant events of the month occurred on the 10th and 13th when
coastal flooding was observed. Water levels were higher on the 13th,
but higher wave heights and more significant wave run up led to more
significant flooding on the 10th. Moderate to major coastal flooding
was observed with extensive damage along the coast due to the
alignment of a high astronomical tide, storm surge, and large
battering nearshore waves. The storm on the 10th also produced
strong to damaging wind across the region.

February was a warm month and temperatures ranged from 5.5 to 7.5
degrees (F) above average.  In fact, it was warm enough that the
month ended as the 5th warmest February on record in Caribou and
Houlton, the 4th warmest in Millinocket, and the 9th warmest in
Bangor. Precipitation and snowfall were both well below average. The
big story was a major warm-up and rain at the end of the month that
caused most of the snow to melt across the north, causing
snowmobile trails to become poor and ending the season for most.
The lack of snow had significant implications for winter
recreational activities causing many to be cancelled or postponed.


March was another warm month and temperatures ranged from 4.5 to 5.5
degrees (F) above average. It was the 6th warmest March on record in
Caribou.  It was the 8th warmest at Houlton, Millinocket, and
Bangor.  Precipitation was well above average, and in Bangor the
8.99 inches of rain (and melted snow) that was observed made it the
wettest March on record. It was also the wettest March on record in
Caribou and Houlton where 5.74 inches and 5.68 inches of rain and
melted snow were observed respectively. In Millinocket, it was the
5th wettest March with 6.17 inches of rain and melted snow. Snowfall
was above average north and below average Downeast. The most
significant event of the month was a snowfall on the 23rd into the
24th that produced 20 to 25 inches of snow in eastern Aroostook
County south of Caribou, and in parts of Piscataquis and northern
Penobscot counties.

April again featured above average temperatures, although just
slightly above average ranging from 0.5 to 2 degrees (F) above
average. Precipitation was below to well below average with the
driest conditions in northwest Aroostook County where precipitation
was only about one third of normal. In Caribou, only 1.02 inches of
rain (and melted snow) was observed making it the 6th driest April
on record. Snowfall was above average in the Central Highlands and
Downeast with 9 inches of snow observed in Bangor.  In Caribou, only
1.4 inches of snow was observed making it the 7th least snowy April
on record.  Ice went out on the Allagash and Saint John Rivers the
2nd week of the month, and ice went out on all northern lakes by the
end of the month. On the afternoon of the 8th, there was a total
solar eclipse that was visible across northern Maine.

May again had above average temperatures that ranged from 2.5 to 4.5
degrees (F) above average.  In Caribou, it tied with 2001 as the 4th
warmest May on record. Houlton and Millinocket observed their 7th
warmest May on record, and in Bangor it was the 12th warmest on
record. The last widespread frost occurred between the 10th and
12th, but some colder northern valleys did have a frost at the end
of the month. Precipitation was mostly below average, but parts of
southern penobscot and western Hancock counties observed slightly
above average precipitation. The first severe weather of the season
was observed on the 23rd when thunderstorms produced wind, causing
trees to be knocked down in parts of Aroostook and Penobscot
Counties. A very strong geomagnetic storm made vivid auroras
visible in many areas on the nights of the 10th through the 12th.

June continued the trend of above average temperatures with
departures of 3 to 4 degrees (F) above average.  It was the warmest
June on record in Caribou. Both Houlton and Millinocket observed
their 6th warmest June, and Bangor observed their 11th warmest June
on record. Precipitation was mostly close to normal. The high
temperature of 96F at Caribou on the 19th tied the all-time record
high temperature, and the low of 71F also tied the all-time warmest
low. The average daily temperature of 83.5 degrees was the warmest
on record. It should be noted, that based on longer existing climate
records nearby Caribou, high temperatures in Caribou may have
been a few degrees higher in the mid to late August 1935 heat
wave. A small area of moderate drought was present along and near
the Quebec border at the start of the month, but was removed by
the end of the month.

Temperatures in July were again well above average and ranged from 2
to 4 degrees (F) above normal.  It was the 3rd warmest July on
record in Caribou, the 4th warmest in Millinocket, 8th warmest in
Houlton, and 9th warmest in Bangor. There were a total of 21 days
with a high temperature of 80F or warmer in Caribou, which tied
with July 2018 for the most 80 degree days in any month since
weather records began. Rainfall was more variable, but mostly near
normal or above normal. There was a zone from around Dover-
Foxcroft to Lincoln with upwards of 250 percent of normal
precipitation due to the remnants of Hurricane Beryl which
produced from 3 to 6 inches of rain in this corridor. The 6.01
inches of rain that was observed in Millinocket made it the 3rd
wettest July since 1903.

August featured temperatures that ranged from near normal along the
coast and in Bangor to 1 to 2 degrees (F) above average across the
north. Only Caribou ended up in the top 10 with the 8th warmest
August on record. Rainfall varied from 70 to 140 percent of normal
with the greatest positive departures in Bangor and across the
Downeast Region. The most significant rain event for Bangor and the
Downeast Region occurred on the 9th when the remnants of tropical
storm Debby produced 1.5 to 2.5 inches of rain. Another event
produced up to 2.5 inches of rain on the 19th into the 20th across
North Woods. Very little in the way of severe weather was
observed. September was significantly warmer and much drier than
average across all of the region. Temperatures ranged from 1 to
3.5 degrees (F) above average with the greatest departures across
the north. it was the 5th warmest September on record in Caribou
and Houlton, and the 6th warmest in Millinocket. Perhaps the most
noteworthy aspect of the month was how dry it was with only 25 to
35 percent of the normal precipitation, except 50 to 60 percent of
normal in the North Woods. It was the 2nd driest September on
record in Caribou, the 4th driest in Houlton and Millinocket, and
the 13th driest in Bangor. By the end of the month, the Drought
Monitor rated Northeast and Central areas as abnormally dry with
moderate drought rated over parts of the Downeast region.

October was warmer than normal with much below average
precipitation. Temperatures ranged from 1.5 to 3.5 degrees (F) above
average. Precipitation ranged from 25 to 50 percent of normal. It
ranked as the 9th warmest October on record in Caribou.  The warmest
day was on the 31st when Caribou had a high of 77F, Bangor 78F,
Millinocket 75F, and Houlton 73F.  The highs in Caribou, Bangor, and
Millinocket were the warmest for so late in the season. The first
freeze was observed in Caribou on the 9th, and in Bangor on the
17th. At Caribou and Bangor, it was the 9th driest October on
record. Millinocket and Houlton observed their 7th and 10th driest
Octobers on record respectively. Moderate drought expanded north to
areas south and east of Katahdin along with Aroostook County along
the New Brunswick border.  The first snowfall of the season was
observed on the 14th and 15th in the North Woods where up to 2
inches of snow as observed.  Fall foliage peaked during the first
week of the month across the north, and around the middle of the
month in Bangor and along the coast.

November was much warmer than normal with below average
precipitation. Temperatures ranged from 4 to 6 degrees (F) above
average, and it was the warmest November on record in Caribou. In
Bangor and Millinocket it was the 4th warmest November, and ranked
as the 6th warmest in Houlton.  Precipitation ranged from 50 to 90
percent of normal with most of it falling during the last third of
the month.  Snowfall was mostly below average, but it was a bit
above average in parts of southern Piscataquis and southern
Aroostook Counties.  Record highs were established at all long term
climate sites on the 6th with highs in the 70s.  The high of 75F in
Bangor tied with 1938 for the warmest temperature so late in the
season. The most significant event of the month was a snowstorm on
the 28th into the 29th that produced as much as 15 inches of snow at
Parkman in Piscataquis County, and 13 inches at Hammond in Aroostook
County.  Elsewhere across the region, amounts were mostly 3 to 8
inches, but with an inch or less for most areas along the coast. By
the end of the month most of the region was in moderate drought with
the exception in northwest Maine where it was abnormally dry.

December featured near to slightly above average temperatures and
slightly above average precipitation. Temperatures ranged from near
average to 2 degrees (F) above average with the greatest positive
departures across northern areas. Precipitation ranged from 100 to
150 percent of normal, except parts of Washington County where
precipitation ranged from 50 to 80 percent of normal.
Snowfall was below average. The most significant event of the month
was a wind and rain storm on the 11th into the 12th that produced
1.5 to 3 inches of rain and wind gusts over 60 mph along the coast.
The rain and mild temperatures wiped out the snowpack. Another rain
event at the end of the month again wiped out all of the snow,
except across higher elevation sites and in spots in the North
Woods. The rain event put a damper on any winter outdoor recreation
across the region.