Wednesday, September 17, 2025
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
WEDNESDAY, SEPTEMBER 17, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0527E
SUNSET: 1750E
MORE CLOUDS THAN SUN TODAY AS A SYSTEM SPINS TO OUR SOUTH….
We had some fog early this morning, but otherwise the sky has
featured a lot of clouds throughout the day with breaks of
sunshine. All in all it’s been a pretty nice day however.
Temperatures are a bit on the cool side again today thanks to
the wind off the ocean. Readings did reach the low 70s for a
time, but has dipped back into the upper 60s early this
afternoon. Dew point values have been generally hanging out in
the mid to upper 50s most of the day.
Winds have been fairly steady out of an easterly direction. The
speed has been averaging at around 9mph for the day so far. The
peak gust so far for the day is 22mph, which occurred just
before 9am this morning.
Visibility was as high as 70 miles for a time early this morning,
but decreased to around 50 miles by mid morning and remained there
through early this afternoon.
The maximum temperature so far today is 71F degrees, which is 1
degree below the normal high of 72F. The minimum temperature
since midnight is 55F degrees, which is equal to the normal low
of 55F.
————————————————————–
Today’s Observations:
7 A.M.
Weather: Scattred altostratus, broken altocumulus, broken cirrostratus
few stratus fractus all quadrants, virga all quadrants
Temperature: 58F; Dew Point: 57F; Relative Humidity: 97%
Wind: ENE @ 10G17 kts
Sea-level pressure: 1022.6 mb; 30.20 in. Hg: falling, then
more rapidly
Visibility: 70 miles, 10 miles ESE-SSW
6-hr Max temp: 58F
6-hr Min temp: 55F
24-hr Precip: 0.00 inches
BHO SA 1155 100 SCT E150 BKN 220 BKN 70 226/58/57/0610G17/020/ FEW
STFRA ALQDS VIRGA ALQDS VSBY 10 ESE-SSW/ 8/776 58013 10058 20055
10 A.M.
Weather: Scattered stratocumulus, scattered altostratus, broken
altocumulus/castellanus broken cirrostratus, broken cirrus
Temperature: 70F; Dew Point: 57F; Relative Humidity: 63%
Wind: E @ 7 kts
Sea-level pressure: 1023.0 mb; 30.21 in. Hg: rising, then falling
Visibility: 50 miles
3-hr Precip: 0.00 inches
BHO SA 1455 20 SCT 90 SCT E120 BKN 220 BKN 250 BKN 50
230/70/57/0907/021/ 8/576 50004
1 P.M.
Weather: Broken altocumulus/castellanus, broken cirrostratus,
broken cirrus, few stratocumulus distant all quadrants, virga
distant SE-SW
Temperature: 69F Dew Point: 59F; Relative Humidity: 70%
Wind: NE @ 9 kts
Sea-level pressure: 1021.8 mb; 30.17 in. Hg: rising, then falling
Visibility: 50 miles
6-hr Max temp: 71F
6-hr Min temp: 58F
6-hr Precip: 0.00 inches
BHO SA 1755 E120 BKN 180 BKN 250 BKN 50 218/69/59/0409/017/
FEW SC DSNT ALQDS VIRGA DSNT SE-SW/ 8/586 58012 10071 20058
————————————————————–
SUMMARY FOR TUESDAY, SEPTEMBER 16, 2025
TEMPERATURE (DEGREES F)
MAX…….71 NORMAL…..73
MIN…….55 NORMAL…..56
MEAN……63 NORMAL…..64
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-1
TOTAL DEPARTURE FOR THE MONTH………………………-21 [-1.5 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..2 DEPARTURE……..-1
TOTAL HEATING UNITS FOR THE MONTH…………….24 DEPARTURE……..-4
TOTAL HEATING UNITS FOR THE SEASON……………44 DEPARTURE……..-2
TOTAL HEATING UNITS LAST SEASON TO DATE……….21 DEPARTURE…….+23
COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..0 DEPARTURE……..-2
TOTAL COOLING UNITS FOR THE MONTH…………….31 DEPARTURE…….-22
TOTAL COOLING UNITS FOR THE SEASON…………..703 DEPARTURE…….+54
TOTAL COOLING UNITS LAST SEASON TO DATE………741 DEPARTURE…….-38
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
F420C (Official)………..20 E @ 12:13 A.M.
VECTOR #1 (1-Sec)……….19 ESE @ 12:23 A.M.
VECTOR #2 (1-Sec)……….19 ENE @ 12:13 A.M.
DAVIS #1……………….19 E @ 12:13 A.M.
DAVIS #2 ………………19 E @ 12:13 A.M.
RMY #1 (Instantaneous)…..19 E @ 12:13 A.M.
RMY #2 (Instantaneous)…..20 ENE @ 12:13 A.M.
MERLIN…………………19 NE
RICHARDS (C5C) (Inst)……18 E @ 12:13 A.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………13 E @ 12:18 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..14 E @ 12:24 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..15 ENE @ 12:14 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 E @ 12:15 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………16 E @ 12:15 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..15 ENE @ 12:15 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..15 ENE @ 12:14 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………15 ENE @ 12:15 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………6.5 ENE [156 total miles]
VECTOR #1……………….6.5
VECTOR #2……………….7.3
DAVIS #1………………..7.0 ENE
DAVIS #2………………..6.9 ENE
RMY #1………………….6.8 ENE
RMY #2………………….7.2 NE
RICHARDS (C5C)…………..7.3
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.14
TOTAL PRECIPITATION FOR THE MONTH…………..2.14 DEPARTURE…..+0.17
TOTAL PRECIPITATION FOR THE YEAR (2025)…….33.47 DEPARTURE…..-3.11
————————————————————–
PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/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
9/1 73/55/64/-5/0.00/221/28 23 NE VEC1 23 ENE RMY 23
9/2 77/58/68/-1/0.00/714/91 18 ESE VEC1 19 ESE RMY 18
9/3 78/57/68/0/0.00/719/92 21 SSW VEC1 21 SSW RMY 21
9/4 81/56/69/+1/0.00/694/89 26 SSW VEC1 27 SSW RMY 28
9/5 82/63/73/+5/0.12/404/52 30 SSW VEC1 31 SSW RMY 33
9/6 84/64/74/+6/1.05/457/59 55 W VEC1 55 W RMY 57 TSTM
9/7 64/56/60/-7/0.97/000/00 16 WNW VEC1 16 NNE RMY 15
9/8 68/49/59/-8/0.00/508/66 21 NW VEC1 21 NW RMY 24
9/9 70/53/62/-5/0.00/697/91 22 ENE VEC1 23 E RMY 23
9/10 65/54/60/-6/0.00/183/24 24 NE VEC1 25 NE RMY 25
9/11 77/51/64/-2/0.00/714/94 21 N VEC1 17 N RMY 18
9/12 71/56/64/-2/0.00/735/97 24 ENE VEC1 24 NNE RMY 23
9/13 76/55/66/+1/T/634/84 26 S VEC1 26 S RMY 25
9/14 79/57/68/+3/0.00/…/.. 15 NE VEC1 15 SW RMY 15
9/15 72/57/65/0/0.00/…/.. 20 N VEC1 19 N RMY 18
9/16 71/55/63/-1/0.00/…/.. 20 E VEC1 19 ESE RMY 19
9/17 The low since midnight is 55F, the daily normal low is 55F.
————————————————————–
SEPTEMBER DAILY RECORDS TO DATE
NONE.
————————————————————–
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR SEPTEMBER 17
HIGH 87F IN 2015
LOW 38F IN 1959
PRECIP 2.73 INCHES IN 1933
PEAK GUST 60 MPH WNW IN 1999
RECORDS FOR SEPTEMBER 18
HIGH 88F IN 1906
LOW 36F IN 1919
PRECIP 4.25 INCHES IN 1996
PEAK GUST 77e MPH WNW IN 1948
TODAY’S REPORT PREPARED BY: Amanda Joly/Matt Douglas
