Tuesday, December 9, 2025
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
TUESDAY, DECEMBER 9, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0702E
SUNSET: 1611E
SUNNY AND COLD AS THE ARCTIC AIR MASS REMAINS IN PLACE….
Clear skies today have allowed for abundant sunshine throughout
the day, however the sun has done little to make it feel warm out
there as we continue under an arctic air mass. It certainly
feels more akin to mid January than early December!
Temperatures are still running well below normal today, with the
low this morning dropping to 9F. We have only recovered to the
mid 20s by early this afternoon. This is a good 15+ degrees below
expected values for the date. The dew point has been holding in
the single digits, and at times near zero today. This is indicating
that the arctic air mass is still over the region.
On the bright side, the wind has been on the light side today.
The strongest winds occurred during the wee hours of this morning,
but the trend has been for less wind as the day has progressed.
The average speed for the day so far is around 9mph. The peak
gust so far for the day is 20mph, which occurred just after 3:30am
this morning.
Visibility has been decent, but not as great as one might expect
with such a dry air mass. The view has been around 60 miles all
day so far.
The maximum temperature so far today is 26F degrees, which is
16 degrees below the normal high of 42F. The minimum temperature
since midnight is 9F degrees, which is 18 degrees below the
normal low of 27F.
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Today’s Observations:
7 A.M.
Weather: Clear, few stratocumulus distant NE-SE, few cirrus distant
ESE-SSW
Temperature: 10F; Dew Point: 3F; Relative Humidity: 72%
Wind: NW @ 9 kts
Sea-level pressure: 1024.2 mb; 30.25 in. Hg: rising, then more slowly
Visibility: 60 miles
6-hr Max temp: 11F
6-hr Min temp: 9F
24-hr Precip: 0.00 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 CLR 60 242/10/3/3209/025/ FEW SC DSNT NE-SE
FEW CI DSNT ESE-SSW/ 8/501 51013 10011 20009
10 A.M.
Weather: Clear, few stratocumulus distant NE, few cirrostratus
distant W-NNW, few cirrus distant W-NW
Temperature: 18F; Dew Point: 4F; Relative Humidity: 52%
Wind: WNW @ 3 kts, wind light
Sea-level pressure: 1024.1 mb; 30.24 in. Hg: steady, then falling
Visibility: 60 miles
3-hr Precip: 0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 CLR 60 241/18/4/2903/024/ FEW SC DSNT NE
FEW CS DSNT W-NNW FEW CI DSNT W-NW WND LGT/ 8/505 58001
1 P.M.
Weather: Thin scattered cirrus, few stratocumulus distant NE,
few cirrostratus distant NW-N
Temperature: 26F; Dew Point: 3F; Relative Humidity: 36%
Wind: SSW @ 4 kts, wind light
Sea-level pressure: 1021.1 mb; 30.15 in. Hg: falling, then more rapidly
Visibility: 60 miles
6-hr Max temp: 26F
6-hr Min temp: 10F
6-hr Precip: 0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 250 -SCT 70 211/26/3/2104/015/ FEW SC DSNT NE
FEW CS DSNT NW-N WND LGT/ 8/505 58030 10026 20010
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SUMMARY FOR MONDAY, DECEMBER 8, 2025
TEMPERATURE (DEGREES F)
MAX…….31 NORMAL…..42
MIN…….12 NORMAL…..27
MEAN……22 NORMAL…..35
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………-13
TOTAL DEPARTURE FOR THE MONTH………………………-57 [-7.3 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY…………….43 DEPARTURE…….+13
TOTAL HEATING UNITS FOR THE MONTH……………290 DEPARTURE…….+56
TOTAL HEATING UNITS FOR THE SEASON………….1407 DEPARTURE…….-31
TOTAL HEATING UNITS LAST SEASON TO DATE……..1215 DEPARTURE……+192
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)………..43 NW @ 05:07 A.M.
VECTOR #1 (1-Sec)……….43 NW @ 05:07 A.M.
VECTOR #2 (1-Sec)……….42 NW @ 05:25 A.M.
DAVIS #1……………….38 NW @ 05:05 A.M.
DAVIS #2 ………………38 NW @ 05:25 A.M.
RMY #1 (Instantaneous)…..44 NW @ 05:07 A.M.
RMY #2 (Instantaneous)…..46 NW @ 05:25 A.M.
MERLIN…………………40 NW
RICHARDS (C5C) (Inst)……42 NW @ 05:07 A.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………28 NW @ 05:13 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..28 NW @ 05:13 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..28 NW @ 05:26 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………29 NW @ 05:13 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………27 NNW @ 05:26 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..28 NW @ 05:13 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..27 NW @ 05:26 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………28 NW @ 05:13 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..13.7 NW [329 total miles]
VECTOR #1………………13.3
VECTOR #2………………13.8
DAVIS #1……………….13.8 NW
DAVIS #2……………….13.5 NNW
RMY #1…………………13.0 NW
RMY #2…………………13.4 NW
RICHARDS (C5C)………….13.6
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.18
TOTAL PRECIPITATION FOR THE MONTH…………..0.91 DEPARTURE…..-0.52
TOTAL PRECIPITATION FOR THE YEAR (2025)…….45.37 DEPARTURE…..-4.53
SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE…..-0.4
TOTAL SNOWFALL FOR THE MONTH………………..0.6 DEPARTURE…..-1.6
TOTAL SNOWFALL FOR THE SEASON (2025-2026)…….0.7 DEPARTURE…..-4.0
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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/…/.. 43 NW VEC1 43 NW RMY 44
12/9 The low since midnight is 9F, the daily normal low is 27F.
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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 9
HIGH 68 IN 1966
LOW -14 IN 1902
PRECIP 3.23 INS. IN 2014
SNOWFALL 10.8 INS. IN 2005
PEAK GUST 66 SE IN 1973
RECORDS FOR DECEMBER 10
HIGH 62 IN 1946
LOW -6 IN 1902
PRECIP 1.67 INS. IN 1907
SNOWFALL 6.0 INS. IN 1905
PEAK GUST 66e SW IN 1940
TODAY’S REPORT PREPARED BY: Matt Douglas
