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Sunday, December 21, 2025

December 21, 2025

BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA SUNDAY, DECEMBER 21, 2025 ALL TIMES ARE…

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BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

SUNDAY, DECEMBER 21, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0710E
SUNSET:  1615E

WINDY WELCOME TO THE WINTER SOLSTICE: SUNSHINE AND
SEASONABLE TEMPERATURES TODAY….

Happy winter solstice! The day started with a brilliant
orange sunrise and plenty of cirrus clouds. As the day
progressed we had an increase in low level clouds, but
there has been plenty of sunshine all day.

Temperatures were more seasonable today, though the blustery
conditions made it feel near the freezing point at times. Dew
point values have dropped from around 34 this morning to 23 by 1pm.

Winds have been quite steady today, first out of the south-
southwest and then shifting to the north-northwest by the early
afternoon. It has been quite gusty, most noticeably this afternoon
with gusts in the 30-35 mph range. The average speed for the day
so far is 19mph, primarily out of the west-northwest. The peak gust
is approximately 46mph, occurring shortly after 1am this morning.

Visibility has been around 40 miles for much of the day and then
increased quite a bit by this afternoon due to drier air moving in
the area.

The maximum temperature so far today is 45F degrees, which is
6 degrees above the normal high of 39F. The minimum temperature
since midnight is 33F degrees, which is 9 degrees below the
normal low of 24F.

————————————————————–

Today’s Observations:

7 A.M.
Weather: Scattered altocumulus, broken cirrus, few stratocumulus
distant NE-SSE
Temperature: 40F; Dew Point: 34F; Relative Humidity: 83%
Wind: WNW @ 17G29 kts, peak wind SW 33mph at 06:22 A.M.
Sea-level pressure: 1011.4 mb; 29.87 in. Hg: falling, then
more slowly
Visibility: 40 miles
6-hr Max temp: 40F
6-hr Min temp: 35F
24-hr Precip: 0.00 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 18 SCT E250 BKN 40 114/40/34/2317G29/987/ FEW SC DSNT NE-SSE
PK WND 2230/22/ 8/551 56017 10040 20035

10 A.M.
Weather: Thinly scattered cirrus, few stratocumulus NW-N, few
altocumulus ENE-S
Temperature: 43F; Dew Point: 28F; Relative Humidity: 55%
Wind: W @ 17G25 kts
Sea-level pressure: 1012.8 mb; 29.91 in. Hg: rising, then
more rapidly
Visibility: 40 miles
3-hr Precip: 0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 250 -SCT 40 128/43/28/2717G25/991/ FEW SC NW-N
FEW AC ENE-S/ 8/551 53014

1 P.M.
Weather: Scattered stratocumulus, thinly scattered cirrus
Temperature: 42F; Dew Point: 23F; Relative Humidity: 46%
Wind: WNW @ 18G27 kts, peak wind WNW 36 mph at 12:01 P.M.
Sea-level pressure: 1012.3 mb; 29.89 in. Hg: falling, then
steady
Visibility: 60 miles
6-hr Max temp: 45F
6-hr Min temp: 40F
6-hr Precip: 0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 55 SCT 250 -SCT 60 123/42/23/3018G27/989/ PK WND 2931/01/
8/501 55005 10045 20040

————————————————————–

SUMMARY FOR SATURDAY, DECEMBER 20, 2025

TEMPERATURE (DEGREES F)
MAX…….36   NORMAL…..39
MIN…….27   NORMAL…..24
MEAN……32   NORMAL…..31

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+1
TOTAL DEPARTURE FOR THE MONTH………………………-91 [-4.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY…………….33  DEPARTURE……..-1
TOTAL HEATING UNITS FOR THE MONTH……………710  DEPARTURE…….+91
TOTAL HEATING UNITS FOR THE SEASON………….1827  DEPARTURE……..+4
TOTAL HEATING UNITS LAST SEASON TO DATE……..1558  DEPARTURE……+269

PEAK WIND GUST (MPH):
Note: Instruments designated #1 = Main Tower, #2 = South Tower,
F420C, Contacting, Merlin, and Richards are all on Main Tower.
E=Estimated *=Last of multiple occurrences

F420C (Official)………..46 WNW  @   02:09 A.M.
VECTOR #1 (1-Sec)……….46 WNW  @   02:09 A.M.
VECTOR #2 (1-Sec)……….50 WNW  @   02:11 A.M.
DAVIS #1……………….45 W    @   02:31 P.M.
DAVIS #2 ………………46 WNW  @   02:08 A.M.
RMY #1 (Instantaneous)…..45 WNW  @   02:06 A.M.
RMY #2 (Instantaneous)…..53 WNW  @   02:11 A.M.
MERLIN…………………M
RICHARDS (C5C) (Inst)……49 WNW  @   02:09 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………32 WNW  @   02:10 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..31 W    @   02:32 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..36 WNW  @   02:10 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………34 W    @   02:33 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………35 WNW  @   02:10 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..30 WNW  @   02:10 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..35 WNW  @   02:10 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………32 WNW  @   02:10 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..14.2 WNW [341 total miles] VECTOR #1………………14.2
VECTOR #2………………15.0
DAVIS #1……………….14.8 WSW
DAVIS #2……………….15.3 W
RMY #1…………………13.6 WSW
RMY #2…………………14.8 WSW
RICHARDS (C5C)………….14.1

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.17
TOTAL PRECIPITATION FOR THE MONTH…………..1.68 DEPARTURE…..-1.88
TOTAL PRECIPITATION FOR THE YEAR (2025)…….46.14 DEPARTURE…..-5.89

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE…..-0.5
TOTAL SNOWFALL FOR THE MONTH………………..2.4 DEPARTURE…..-4.7
TOTAL SNOWFALL FOR THE SEASON (2025-2026)…….2.5 DEPARTURE…..-7.1

————————————————————–

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN)/SUN(%)/PEAK GUST/VEC1/RMY GUST
PEAK GUST: F420C (Official)
VEC1: Vector #1 1-second gust
RMY:  R.M. Young #1 wind gust recording system (Instantaneous)
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data

12/1   42/27/35/-2/T/0.0/547/98          37 WNW VEC1 37 WNW RMY 38
12/2   36/27/32/-5/0.85/T/000/00         38 N   VEC1 38 NNE RMY 38
12/3   37/27/32/-4/0.06/0.6/423/76       28 NW  VEC1 29 NNW RMY 30
12/4   38/15/27/-9/T/T/255/46            60 NW  VEC1 59 WNW RMY 61
12/5   25/8/17/-19/T/T/510/92            30 NW  VEC1 30 NW  RMY 30
12/6   39/25/32/-3/T/T/122/22            21 W   VEC1 21 W   RMY 22
12/7   39/27/33/-2/0.00/0.0/248/45       24 W   VEC1 24 W   RMY 24
12/8   31/12/22/-13/T/T/457/83           43 NW  VEC1 43 NW  RMY 44
12/9   28/9/19/-15/0.00/0.0/452/82       33 SSW VEC1 33 SSW RMY 33
12/10  46/28/37/+3/0.04/T/187/34         50 SSW VEC1 50 SSW RMY 51
12/11  37/21/29/-5/0.00/0.0/450/82       51 WNW VEC1 51 WNW RMY 53
12/12  33/18/26/-8/0.00/0.0/532/97       41 W   VEC1 41 W   RMY 42
12/13  34/23/29/-4/0.00/0.0/038/07       28 SW  VEC1 28 SW  RMY 31
12/14  31/15/23/-10/0.13/1.8/000/00      39 NNW VEC1 39 NNW RMY 40
12/15  23/10/17/-16/0.00/0.0/496/91      40 NW  VEC1 40 NW  RMY 42
12/16  36/19/28/-4/0.00/0.0/437/80       29 SW  VEC1 29 SW  RMY 30
12/17  45/25/35/+3/0.00/0.0/196/36       43 SW  VEC1 42 SW  RMY 43
12/18  47/32/40/+8/0.00/0.0/…/..       32 S   VEC1 32 S   RMY 34
12/19  58/32/45/+13/0.60/0.0/…/..      79 S   VEC1 79 S   RMY 81
12/20  36/27/32/+1/0.00/0.0/…/..       46 WNW VEC1 46 WNW RMY 45

12/21  The low since midnight is 33F, the daily normal low is 24F.

————————————————————–

DECEMBER DAILY RECORDS TO DATE

12/19 PEAK GUST OF 79 MPH S,
BEAT THE OLD RECORD OF 68 MPH NE IN 1986.

————————————————————–

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)

RECORDS FOR DECEMBER 21
HIGH 62 IN 2018
LOW -10 IN 1942
PRECIP 2.37 INS. IN 1946
SNOWFALL 11.4 INS. IN 1954
PEAK GUST 77 MPH SSE IN 1957

RECORDS FOR DECEMBER 22
HIGH 63 IN 2013
LOW -5 IN 1921
PRECIP 1.52 INS. IN 1975
SNOWFALL 8.8 INS. IN 1975
PEAK GUST 62 MPH WNW IN 1998

TODAY’S REPORT PREPARED BY: Amanda Joly

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Blue Hill Observatory & Science Center · Legal

Data Use & Privacy Policy

Please read the full Policy before accessing Observatory data · Effective January 1, 2025

Notice: By accessing, downloading, or using any Blue Hill Observatory data or services, you unconditionally accept and agree to be bound by this Policy in its entirety. If you do not agree, you may not access or use Observatory data.
Effective January 1, 2025 · Milton, Massachusetts · bluehill.org
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