Friday, December 19, 2025

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

FRIDAY, DECEMBER 19, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0709E
SUNSET:  1614E

WIND TAKES CENTER STAGE TODAY! RECORD SOUTHERLIES, RAIN
AND FOG TODAY AT BLUE HILL….

Today has been quite a busy day on the summit, with the arrival
of record breaking winds along with some much needed rain. So
far we have received 0.35 inches of rain today with more in the
area. This will help a bit, as we are well under 6 inches for
the season.

Temperatures have warmed above average values today, which is
probably a good thing with the wind and precipitation. Overnight
we were at 45F which is higher than our average high for this
time of year. The temperature climbed to 58F, which is the high
so far for the day and one degree short of the record high for
the date of 59F. Due to the rain we have had high dew points,
which have been in the 50’s for much of today.

The wind has been something today! We have had strong southerly
flow all day, starting into last night. So far the average is
an impressive 25mph. We have had frequent gusts ranging from
40-60mph which mostly started to pick up after 11am. The peak
gust for the day so far is 79mph, which occurred at 11:48am.
This gust breaks the old record of 68mph for December 19th set
in 1986. A special report will be prepared after this system moves
out, in case another higher wind occurs.

Visibility has been heavily impacted by fog and rain today. We
have fluctuated between 1/2 mile to about 5 miles.

The maximum temperature so far today is 58F degrees, which is
18 degrees above the normal high of 40F. The minimum temperature
since midnight is 45F degrees, which is 21 degrees above the
normal low of 24F.

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Today’s Observations:

7 A.M.
Weather: Sky obscured, vertical visibility 200 ft.
Temperature: 54F; Dew Point: 52F; Relative Humidity: 94%
Wind: S @ 18G25 kts, peak wind S 32mph at 06:36 A.M.
Sea-level pressure: 1008.8 mb; 29.79 in. Hg: falling, then
more rapidly
Visibility: 1 mile, fog
6-hr Max temp: 54F
6-hr Min temp: 37F
24-hr Precip: 0.02 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 X W2 1F 088/54/52/1718G25/979/ PRESFR PK WND 1728/36/
8//// 58049 6002/ 70002 10054 20037

10 A.M.
Weather: Rain showers, sky obscured, vertical visibility 200 ft.
Temperature: 56F; Dew Point: 56F; Relative Humidity: 100%
Wind: S @ 22G32 kts, peak wind S 46mph at 09:17 A.M.
Sea-level pressure: 1002.3 mb; 29.60 in. Hg: falling, then
more rapidly
Visibility: 1/2 mile, fog
3-hr Precip: 0.11 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 X W2 1/2RW-F 023/56/56/1722G32/960/ PRESFR
PK WND 1740/17/ 8//// 58065 6011/

1 P.M.
Weather: Rain showers, overcast stratus
Temperature: 57F; Dew Point: 57F; Relative Humidity: 100%
Wind: SSW @ 36G54 kts
Sea-level pressure: 990.7 mb; 29.26 in. Hg: falling, then
more slowly
Visibility: 5 miles, fog
6-hr Max temp: 58F
6-hr Min temp: 53F
6-hr Precip: 0.33 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 2 OVC 5RW-F 907/57/57/1936G54/926/ PRESFR
PK WND 1767/06/ 8/6// 58116 6033/ 10058 20053

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SUMMARY FOR THURSDAY, DECEMBER 18, 2025

TEMPERATURE (DEGREES F)
MAX…….47   NORMAL…..40
MIN…….32   NORMAL…..24
MEAN……40   NORMAL…..32

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+8
TOTAL DEPARTURE FOR THE MONTH……………………..-105 [-6.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY…………….25  DEPARTURE……..-8
TOTAL HEATING UNITS FOR THE MONTH……………657  DEPARTURE……+105
TOTAL HEATING UNITS FOR THE SEASON………….1774  DEPARTURE…….+18
TOTAL HEATING UNITS LAST SEASON TO DATE……..1493  DEPARTURE……+281

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)………..32 SW   @   10:00 P.M.
VECTOR #1 (1-Sec)……….32 S    @   10:07 P.M.
VECTOR #2 (1-Sec)……….33 SSE  @   10:00 P.M.
DAVIS #1……………….31 S    @   05:12 P.M.
DAVIS #2 ………………40 S    @   10:07 P.M.
RMY #1 (Instantaneous)…..34 SSE  @   09:56 P.M.
RMY #2 (Instantaneous)…..35 SSE  @   10:23 P.M.
MERLIN…………………33 S
RICHARDS (C5C) (Inst)……31 SSE  @   09:56 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………25 S    @   09:46 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..24 S    @   09:46 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..25 SSE  @   09:52 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………23 SSE  @   08:19 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………27 S    @   09:40 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..23 S    @   09:46 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..26 SSE  @   09:56 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………22 SSE  @   10:31 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..12.6 S [302 total miles] VECTOR #1………………12.7
VECTOR #2………………13.5
DAVIS #1……………….12.2 SSW
DAVIS #2……………….13.2 SSW
RMY #1…………………12.2 SSW
RMY #2…………………13.5 SSW
RICHARDS (C5C)………….12.6

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.02 DEPARTURE…..-0.15
TOTAL PRECIPITATION FOR THE MONTH…………..1.10 DEPARTURE…..-2.11
TOTAL PRECIPITATION FOR THE YEAR (2025)…….45.56 DEPARTURE…..-6.12

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE…..-0.4
TOTAL SNOWFALL FOR THE MONTH………………..2.4 DEPARTURE…..-3.7
TOTAL SNOWFALL FOR THE SEASON (2025-2026)…….2.5 DEPARTURE…..-6.1

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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  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  The low since midnight is 45F, the daily normal low is 24F.

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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 19
HIGH 59 IN 1899
LOW -1 IN 1919
PRECIP 2.06 INS. IN 1986
SNOWFALL 14.1 INS. IN 1945
PEAK GUST 68 NE IN 1986

RECORDS FOR DECEMBER 20
HIGH 61 IN 1957
LOW -16 IN 1942
PRECIP 1.69 INS. IN 1936
SNOWFALL 13.7 INS. IN 2009
PEAK GUST 75 MPH S IN 2002

TODAY’S REPORT PREPARED BY: Amanda Joly