Thursday, August 21, 2025
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
THURSDAY, AUGUST 21, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0458E
SUNSET: 1836E
CONTINUED COOL WITH CLOUDS DOMINATING ONCE AGAIN AND A BRISK
ONSHORE WIND….
We did see a few peeks of sunshine early this morning,
otherwise clouds have been the dominant feature of the day.
Low level stratocumulus clouds are being joined by bubbling
cumulus clouds which are getting moderate at times. There’s
enough instability aloft that even some intermittent rain
showers developed starting late this morning. The interplay
of the two cloud types is made for a “stormy” look to the sky
for a while this morning, especially since the clouds have
been racing in from the east-northeast at a pretty good clip.
We are on the very outer edge of Hurricane Erin’s circulation,
combined with high pressure building to the north and northwest,
a rather brisk onshore flow has developed today.
Temperatures are once again well below normal for the day.
Readings have only reached the mid 60s so far. This is once
again around 15 degrees below what would normally be expected
on this date. Dew point values have been holding in the upper
50s, indicative of a somewhat moist flow off the ocean.
The wind started off on the light side early this morning, but
quickly ramped up during the mid to late morning hours. The
northeast to east-northeast flow has been averaging around
11mph for the day so far. Gusts are frequently exceeding 20mph
with a peak so far of 31mph, which occurred just before 11am
this morning.
Visibility was fairly average through the morning, holding
at around 40 miles. However there has been some improvement
early this afternoon, especially well to the northwest where
drier air exists. The view is up to 60 miles, although it is
briefly reduced in areas where showers are moving through.
The maximum temperature so far today is 67F degrees, which is
13 degrees below the normal high of 80F. The minimum temperature
since midnight is 54F degrees, which is 8 degrees below the
normal low of 62F.
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Today’s Observations:
7 A.M.
Weather: Scattered stratocumulus, scattered altocumulus/castellanus,
broken cirrostratus, few lower stratus fractus E-ESE and distant SW-NW
Temperature: 60F; Dew Point: 58F; Relative Humidity: 92%
Wind: NNE @ 7 kts
Sea-level pressure: 1020.3 mb; 30.13 in. Hg: falling, then rising
Visibility: 40 miles
6-hr Max temp: 60F
6-hr Min temp: 54F
24-hr Precip: 0.51 inches
BHO SA 1155 25 SCT 80 SCT 180 BKN 40 203/60/58/0307/013/
FEW LWR STFRA E-ESE AND DSNT SW-NW/ 8/588 53004 6000/ 70051
10060 20054
10 A.M.
Weather: Broken stratocumulus, broken cumulus
Temperature: 64F; Dew Point: 58F Relative Humidity: 80%
Wind: ENE @ 14G26 kts, peak wind ENE 30mph at 9:46 A.M.
Sea-level pressure: 1019.6 mb; 30.11 in. Hg: falling, then rising
Visibility: 40 miles
3-hr Precip: 0.00 inches
BHO SA 1455 E25 BKN 35 BKN 40 196/64/58/0614G26/011/ PK WND 0626/46/
8/800 55007
1 P.M.
Weather: Broken stratocumulus, overcast stratocumulus, breaks in
overcast distant NW-NE, virga distant SSE-WSW
Temperature: 64F Dew Point: 58F; Relative Humidity: 80%
Wind: ENE @ 15G24 kts
Sea-level pressure: 1018.5 mb; 30.08 in. Hg: rising, then falling
Visibility: 60 miles
6-hr Max temp: 67F
6-hr Min temp: 60F
6-hr Precip: Trace
BHO SA 1755 E27 BKN 45 OVC 60 185/64/58/0615G24/008/
BINOVC DSNT NW-NE VIRGA DSNT SSE-WSW/ 8/5// 58011 6000/
10067 20060
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SUMMARY FOR WEDNESDAY, AUGUST 20, 2025
TEMPERATURE (DEGREES F)
MAX…….63 NORMAL…..80
MIN…….51 NORMAL…..62
MEAN……57 NORMAL…..71
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………-14
TOTAL DEPARTURE FOR THE MONTH………………………-23 [-1.4 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..8 DEPARTURE……..+8
TOTAL HEATING UNITS FOR THE MONTH…………….12 DEPARTURE……..+7
TOTAL HEATING UNITS FOR THE SEASON……………13 DEPARTURE……..+1
TOTAL HEATING UNITS LAST SEASON TO DATE………..5 DEPARTURE……..+8
COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..0 DEPARTURE……..-7
TOTAL COOLING UNITS FOR THE MONTH……………135 DEPARTURE…….-12
TOTAL COOLING UNITS FOR THE SEASON…………..646 DEPARTURE……+112
TOTAL COOLING UNITS LAST SEASON TO DATE………643 DEPARTURE……..+3
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 ENE @ 05:12 P.M.
VECTOR #1 (1-Sec)……….22 ENE @ 11:55 A.M.
VECTOR #2 (1-Sec)……….21 ENE @ 05:08 P.M.
DAVIS #1……………….21 ENE @ 11:56 A.M.
DAVIS #2 ………………21 E @ 11:55 A.M.
RMY #1 (Instantaneous)…..21 ENE @ 05:11 P.M.
RMY #2 (Instantaneous)…..22 ENE @ 11:55 A.M.
MERLIN…………………19 NE
RICHARDS (C5C) (Inst)……20 @ 11:35 A.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 ENE @ 05:07 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..14 @ 08:03 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..16 @ 11:56 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………15 E @ 11:56 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………16 E @ 11:56 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..14 ENE @ 05:15 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..16 ENE @ 11:56 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………14 @ 11:56 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………8.9 ENE [213 total miles]
VECTOR #1……………….8.6
VECTOR #2……………….9.6
DAVIS #1………………..9.4 E
DAVIS #2………………..9.5 E
RMY #1………………….8.9 E
RMY #2………………….9.5 ENE
RICHARDS (C5C)…………..9.3
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.51 DEPARTURE…..+0.38
TOTAL PRECIPITATION FOR THE MONTH…………..1.82 DEPARTURE…..-0.77
TOTAL PRECIPITATION FOR THE YEAR (2025)…….31.27 DEPARTURE…..-2.02
————————————————————–
PRELIMINARY CLIMATE SUMMARY FOR AUGUST 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
8/1 71/57/64/-9/0.44/546/63 28 NE VEC1 28 NE RMY 27
8/2 75/54/65/-8/0.00/838/97 18 NNW VEC1 18 NNW RMY 18
8/3 83/59/71/-2/0.00/784/91 21 SSW VEC1 21 SSW RMY 21
8/4 84/61/73/0/0.00/757/88 17 W VEC1 17 W RMY 17
8/5 73/62/68/-5/0.00/480/56 28 NE VEC1 27 NE RMY 28
8/6 77/61/69/-4/0.00/248/29 17 ENE VEC1 17 ENE RMY 16
8/7 81/61/71/-2/0.00/665/78 18 ESE VEC1 18 ESE RMY 17
8/8 83/61/72/0/0.00/834/98 21 SSW VEC1 21 SSW RMY 21
8/9 83/60/72/0/0.00/814/96 22 S VEC1 22 SSW RMY 22
8/10 89/61/75/+3/0.00/761/90 22 S VEC1 22 S RMY 21
8/11 94/67/81/+9/0.00/792/94 20 W VEC1 19 W RMY 19
8/12 93/68/81/+9/0.00/806/96 21 SSW VEC1 21 SSW RMY 21
8/13 88/66/77/+5/0.00/344/41 25 SW VEC1 25 SW RMY 25
8/14 90/68/79/+7/0.68/426/51 35 NE VEC1 34 NE RMY 36 TSTM
8/15 75/63/69/-3/0.00/783/96 29 NE VEC1 29 ENE RMY 31
8/16 86/62/74/+2/0.00/730/88 23 S VEC1 24 S RMY 23
8/17 89/64/77/+5/0.19/414/50 41 NE VEC1 43 NE RMY 42 TSTM
8/18 68/55/62/-9/0.00/627/76 32 NE VEC1 34 NE RMY 34
8/19 73/54/64/-7/0.00/560/68 20 SE VEC1 19 SE RMY 18
8/20 63/51/57-14/0.51/008/01 22 ENE VEC1 22 ENE RMY 21
8/21 The low since midnight is 54F, the daily normal low is 62F.
————————————————————–
AUGUST 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 AUGUST 21
HIGH 92F IN 1937, 1995
LOW 47F IN 1982
PRECIP 2.84 INCHES IN 1888
PEAK GUST 54 MPH WSW IN 2004
RECORDS FOR AUGUST 22
HIGH 90F IN 1939
LOW 42F IN 1894
PRECIP 2.28 INCHES IN 1935
PEAK GUST 47 MPH ESE IN 2021 [TROPICAL STORM HENRI]
TODAY’S REPORT PREPARED BY: MFD
