Monday, December 15, 2025

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

MONDAY, DECEMBER 15, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0707E
SUNSET:  1612E

SUNNY BUT VERY COLD WEATHER TODAY FOLLOWING YESTERDAY’S SNOWFALL….

The total snowfall for the event yesterday was 1.8″, which melted
down to 0.13″ of liquid. This was the biggest snow event of the
young winter season so far. However both precipitation and snowfall
continue to run below normal for the month and season to date.

Today has featured an abundance of sunshine with clear skies,
however we are under another arctic air mass, as such the sun is
doing little to make it feel warm today. Add a gusty breeze to
the mix and we’ve seen wind chill values that have been as low as
-10F this morning. Even into early this afternoon, those values
are still reaching down into the single digits.

Temperatures are once again well below normal. We started the
day at 10F, and have only recovered to the low 20s by early this
afternoon. The normal high for the date should be 40F! Dew point
values have been holding in the single digits all day, indicative
of the arctic air mass in place.

As mentioned, the wind has been on the busy side today, generally
out of the northwest. The average speed for the day so far is
around 17mph. Frequent gusts of 25-35mph have been occurring
through the day. The peak gust for the day so far is 37mph, which
has occurred twice, first back around 1:20am, and then just after
12:30pm.

Visibility has been decent today, improving from around 50 miles
early this morning to around 70 miles by early this afternoon.

The maximum temperature so far today is 22F degrees, which is
18 degrees below the normal high of 40F. The minimum temperature
since midnight is 10F degrees, which is 15 degrees below the
normal low of 25F.

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Today’s Observations:

7 A.M.
Weather: Clear, few stratocumulus offshore distant NE-SE-SSW,
few altocumulus distant N-NNE
Temperature: 11F; Dew Point: 3F; Relative Humidity: 70%
Wind: NW 14G20 kts
Sea-level pressure: 1018.3 mb; 30.07 in. Hg: rising unsteadily
Visibility: 50 miles
6-hr Max temp: 14F
6-hr Min temp: 10F
24-hr Precip: 0.10 inches
24-hr Snowfall: 1.4 inches
Snow Depth: 2 inches
BHO SA 1155 CLR 50 183/11/3/3214G20/007/ FEW SC OFFSHR DSNT NE-SE-SSW
FEW AC DSNT N-NNE TOTAL NEW SNW PST 24 HRS 1.4 INS/ 8/550 4/002 52031
70010 10014 20010

10 A.M.
Weather: Clear, few stratocumulus distant all quadrants, few cirrus
distant SW-WNW
Temperature: 17F; Dew Point: 5F; Relative Humidity: 59%
Wind: WNW @ 16G26 kts, peak wind WNW 32mph at 9:01 A.M.
Sea-level pressure: 1020.3 mb; 30.13 in. Hg: rising, then more slowly
Visibility: 60 miles
3-hr Precip: 0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 CLR 60 203/17/5/3016G26/013/ FEW SC DSNT ALQDS
FEW CI DSNT SW-WNW PK WND 3028/01/ 8/501 51020

1 P.M.
Weather: Broken cirrus, few stratocumulus distant all quadrants
Temperature: 21F; Dew Point: 7F; Relative Humidity: 54%
Wind: NW @ 17G27 kts, peak wind NW 37mph at 12:34 P.M.
Sea-level pressure: 1018.3 mb; 30.07 in. Hg: falling, then more rapidly
Visibility: 70 miles
6-hr Max temp: 22F
6-hr Min temp: 11F
6-hr Precip: 0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 2 inches
BHO SA 1755 E250 BKN 70 183/21/7/3217G27/007/ FEW SC DSNT ALQDS
PK WND 3132/34/ 8/501 4/002 58020 10022 20011

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SUMMARY FOR SUNDAY, DECEMBER 14, 2025

TEMPERATURE (DEGREES F)
MAX…….31   NORMAL…..41
MIN…….15   NORMAL…..25
MEAN……23   NORMAL…..33

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………-10
TOTAL DEPARTURE FOR THE MONTH………………………-96 [-7.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY…………….42  DEPARTURE…….+10
TOTAL HEATING UNITS FOR THE MONTH……………517  DEPARTURE…….+95
TOTAL HEATING UNITS FOR THE SEASON………….1634  DEPARTURE……..+9
TOTAL HEATING UNITS LAST SEASON TO DATE……..1389  DEPARTURE……+245

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)………..39 NNW  @   09:25 P.M.
VECTOR #1 (1-Sec)……….39 NNW  @   07:29 P.M.
VECTOR #2 (1-Sec)……….41 NW   @   06:42 P.M.
DAVIS #1……………….38 NNW  @   07:27 P.M.
DAVIS #2 ………………34 N    @   07:21 P.M.
RMY #1 (Instantaneous)…..40 NNW  @   07:40 P.M.
RMY #2 (Instantaneous)…..42 NW   @   06:42 P.M.
MERLIN…………………35 N
RICHARDS (C5C) (Inst)……38 NNW  @   07:27 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………25 NNW  @   08:10 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..24 NNW  @   06:43 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..26 NW   @   06:43 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………24 NNW  @   10:52 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………25 NNW  @   06:43 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..24 NNW  @   06:43 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..26 NW   @   06:43 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………24 NNW  @   09:24 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………9.9 NNW [238 total miles] VECTOR #1………………10.1
VECTOR #2………………10.4
DAVIS #1………………..9.5 NW
DAVIS #2………………..9.2 NNW
RMY #1…………………10.1 NW
RMY #2…………………10.3 NW
RICHARDS (C5C)………….10.1

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.10 DEPARTURE…..-0.08
TOTAL PRECIPITATION FOR THE MONTH…………..1.08 DEPARTURE…..-1.43
TOTAL PRECIPITATION FOR THE YEAR (2025)…….45.54 DEPARTURE…..-5.44

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..1.4 DEPARTURE…..+1.0
TOTAL SNOWFALL FOR THE MONTH………………..2.4 DEPARTURE…..-2.1
TOTAL SNOWFALL FOR THE SEASON (2025-2026)…….2.5 DEPARTURE…..-4.5

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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  The low since midnight is 10F, the daily normal low is 25F.

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DECEMBER DAILY RECORDS TO DATE

NONE.

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

RECORDS FOR DECEMBER 15
HIGH 64 IN 1975
LOW 4 IN 1900, 1905, 1933
PRECIP 1.80 INS. IN 1981
SNOW 7.5 INS. IN 1951
PEAK GUST 65 MPH NW IN 1991

RECORDS FOR DECEMBER 16
HIGH 61 IN 1971
LOW -2 IN 1930
PRECIP 1.88 INS. IN 2022
SNOW 8.5 INS. IN 2007
WIND 73 MPH SSE IN 1982

TODAY’S REPORT PREPARED BY: Matt Douglas