Thursday, September 18, 2025
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
THURSDAY, SEPTEMBER 18, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0528E
SUNSET: 1748E
SHOWERS AND THUNDERSTORMS EARLY THIS MORNING TAPERED TO DRIZZLE
FOR A TIME BEFORE ENDING….
A period of showers and thunderstorms moved through during the
wee hours of the morning leaving 0.43″ of rain in the gauge.
The showers tapered to drizzle which persisted through the late
morning hours before finally coming to an end. An additional
0.01″ of water was left in the gauge from the drizzle. As of
the 1pm observation, the air was gradually drying out with
overcast skies. A clearing line is being observed off to the
southwest through north.
Temperatures have been slow to warm today due to the cloud
cover, but are approaching the 70F degree mark by early this
afternoon. More notably the humidity level has gone up today
as the dew point has reached the mid 60s by early this
afternoon, giving a bit of a muggy feel out there.
Winds have been quite light and variable today. The average
speed for the day so far is only 6mph. The peak gust so far
for the day is 15mph, which occurred just after 6am this
morning.
Visibility was very limited through the morning as we were
in the clouds (dense fog). We could only see 1/16th to 1/8th
of a mile for most of the morning. However, the view has
improved markedly early this afternoon as the visibility has
reached 60 miles!
The maximum temperature so far today is 69F degrees, which is
3 degrees below the normal high of 72F. The minimum temperature
since midnight is 61F degrees, which is 6 degrees above the
normal low of 55F.
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Today’s Observations:
7 A.M.
Weather: Sky obscured, vertical visibility 200ft, light drizzle
Temperature: 61F; Dew Point: 61F; Relative Humidity: 100%
Wind: NNE @ 6 kts, wind light
Sea-level pressure: 1015.5 mb; 29.99 in. Hg: falling, then more slowly
Visibility: 1/8 mile, fog
6-hr Max temp: 62F
6-hr Min temp: 61F
24-hr Precip: 0.43 inches
BHO SA 1155 X W2 1/8L-F 155/61/61/0306/999/ WND LGT/ 8////
56002 6038/ 70043 10062 20061
10 A.M.
Weather: Sky obscured, vertical visibility 300ft, light drizzle
Temperature: 63F; Dew Point: 63F; Relative Humidity: 100%
Wind: NE @ 2 kts, wind light
Sea-level pressure: 1015.6 mb; 29.99 in. Hg: rising, then falling
Visibility: 3/4 mile, fog
3-hr Precip: 0.01 inches
BHO SA 1455 X W3 3/4L-F 156/63/63/0402/999/ WND LGT/ 8////
50001 6001/
1 P.M.
Weather: Overcast stratocumulus, clearing line distant SW-NW-NNE
Temperature: 69F Dew Point: 65F; Relative Humidity: 86%
Wind: W @ 3 kts, wind light
Sea-level pressure: 1014.0 mb; 29.94 in. Hg: falling, then more rapidly
Visibility: 60 miles
6-hr Max temp: 69F
6-hr Min temp: 61F
6-hr Precip: 0.01 inches
BHO SA 1755 E10 OVC 60 140/69/65/2803/994/ CLRG LINE DSNT SW-NW-NNE
WND LGT/ 8/5// 58016 6001/ 10069 20061
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SUMMARY FOR WEDNESDAY, SEPTEMBER 17, 2025
TEMPERATURE (DEGREES F)
MAX…….71 NORMAL…..72
MIN…….55 NORMAL…..55
MEAN……63 NORMAL…..64
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-1
TOTAL DEPARTURE FOR THE MONTH………………………-22 [-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…………….26 DEPARTURE……..-6
TOTAL HEATING UNITS FOR THE SEASON……………46 DEPARTURE……..-4
TOTAL HEATING UNITS LAST SEASON TO DATE……….21 DEPARTURE…….+25
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…….-27
TOTAL COOLING UNITS FOR THE SEASON…………..703 DEPARTURE…….+49
TOTAL COOLING UNITS LAST SEASON TO DATE………749 DEPARTURE…….-46
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)………..22 E @ 08:52 A.M.
VECTOR #1 (1-Sec)……….22 E @ 08:52 A.M.
VECTOR #2 (1-Sec)……….21 NE @ 06:31 A.M.
DAVIS #1……………….20 NE @ 06:31 A.M.
DAVIS #2 ………………21 E @ 08:02 A.M.
RMY #1 (Instantaneous)…..21 NE @ 06:29 A.M.
RMY #2 (Instantaneous)…..21 NE @ 06:29 A.M.
MERLIN…………………19 E
RICHARDS (C5C) (Inst)……20 E @ 08:24 A.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 NE @ 06:29 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..15 NE @ 06:20 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..15 NE @ 06:27 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 E @ 08:09 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 NE @ 06:26 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..14 E @ 08:09 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..15 NE @ 06:26 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………14 E @ 08:53 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………8.8 ENE [210 total miles]
VECTOR #1……………….8.6
VECTOR #2……………….9.4
DAVIS #1………………..9.2 ENE
DAVIS #2………………..9.3 ENE
RMY #1………………….8.7 ENE
RMY #2………………….9.2 ENE
RICHARDS (C5C)…………..9.1
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.43 DEPARTURE…..+0.28
TOTAL PRECIPITATION FOR THE MONTH…………..2.57 DEPARTURE…..+0.45
TOTAL PRECIPITATION FOR THE YEAR (2025)…….33.90 DEPARTURE…..-2.83
————————————————————–
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 71/55/63/-1/T/…/.. 22 E VEC1 22 E RMY 21
9/18 The low since midnight is 61F, the daily normal low is 55F.
————————————————————–
SEPTEMBER 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 SEPTEMBER 18
HIGH 88F IN 1906
LOW 36F IN 1919
PRECIP 4.25 INCHES IN 1996
PEAK GUST 77e MPH WNW IN 1948
RECORDS FOR SEPTEMBER 19
HIGH 87F IN 1906,1983
LOW 37F IN 1929
PRECIP 3.69 INCHES IN 1936
PEAK GUST 55 MPH S IN 2012
TODAY’S REPORT PREPARED BY: Matt Douglas/Amanda Joly
