Monday, August 18, 2025

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

MONDAY, AUGUST 18, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0455E
SUNSET:  1840E

A TASTE OF EARLY FALL TODAY WITH EXCELLENT VISIBILITY….

A cold front passed through the area last evening bringing some
showers and even a rumble of thunder. 0.19″ of rain was recorded
from this system. But the big story was the abrupt wind shift
from south-southwest to northeast which brought much cooler
and drier air into the region. As a matter of fact, the
temperature dropped 10 degrees in 1 hour between 8pm and 9pm
last night. Also a wind gust of over 40mph accompanied the frontal
passage.

All of this has led us to a rather refreshing day today. We did
start the day with a deck of mainly stratocumulus clouds, but
these moved out by mid morning leaving us with plenty of sun
for the balance of the day.

Temperatures dropped into the upper 50s early this morning and
have only recovered to the mid to upper 60s by early this
afternoon. This is some 10-15 degrees below the normal high
temperature for the date. Dew point readings are 20F+ degrees
below yesterday’s values with reading holding right around 50F
all day today. This is much more pleasant and fall-like.

The wind has been fairly busy today averaging at around 13mph
out of the northeast and east-northeast. The peak gust so far
for the day is 32mph, which occurred in the wee hours of the
day, just after 12:45am.

Visibility has been exceptional all day with a crisp view of
80 miles!

The maximum temperature so far today is 68F degrees, which is
12 degrees below the normal high of 80F. The minimum temperature
since midnight is 59F degrees, which is 4 degrees below the
normal low of 63F.

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Today’s Observations:

7 A.M.
Weather: Overcast stratocumulus, few breaks in overcast
distant WNW-N-ESE, few lower stratus fractus distant WNW-NW
Temperature: 59F; Dew Point: 50F; Relative Humidity: 72%
Wind: NE @ 12G21 kts
Sea-level pressure: 1021.4 mb; 30.16 in. Hg: rising, then more slowly
Visibility: 80 miles
6-hr Max temp: 62F
6-hr Min temp: 59F
24-hr Precip:  0.19 inches
BHO SA 1155 E35 OVC 80 214/59/50/0512G21/016/ FEW BINOVC DSNT
WNW-N-ESE FEW LWR STFRA DSNT WNW-NW/ 8/5// 51026 70019 10062 20059

10 A.M.
Weather: Thin broken cirrus, few stratocumulus distant ESE-S-W-N
Temperature: 64F; Dew Point: 50F Relative Humidity: 60%
Wind: ENE @ 11G19 kts
Sea-level pressure: 1022.9 mb; 30.21 in. Hg: rising, then more slowly
Visibility: 80 miles
3-hr Precip: 0.00 inches
BHO SA 1455 E250 -BKN 80 229/64/50/0611G19/021/ FEW SC DSNT
ESE-S-W-N/ 8/501 51015

1 P.M.
Weather: Thin broken cirrus, few stratocumulus distant SE, and
distant SW, and distant N
Temperature: 66F Dew Point: 49F; Relative Humidity: 54%
Wind: E @ 9G17 kts
Sea-level pressure: 1023.1 mb; 30.21 in. Hg: steady, then rising
Visibility: 80 miles
6-hr Max temp: 68F
6-hr Min temp: 59F
6-hr Precip:  0.00 inches
BHO SA 1755 E250 -BKN 231/66/49/0809G17/021/ FEW SC DSNT SE AND
DSNT SW AND DSNT N/ 8/001 53002 10068 20059

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SUMMARY FOR SUNDAY, AUGUST 17, 2025

TEMPERATURE (DEGREES F)
MAX…….89   NORMAL…..80
MIN…….64   NORMAL…..63
MEAN……77   NORMAL…..72

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+5
TOTAL DEPARTURE FOR THE MONTH……………………….+7 [+0.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..0  DEPARTURE………0
TOTAL HEATING UNITS FOR THE MONTH……………..0  DEPARTURE……..-4
TOTAL HEATING UNITS FOR THE SEASON…………….1  DEPARTURE…….-10
TOTAL HEATING UNITS LAST SEASON TO DATE………..2  DEPARTURE……..-1

COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY…………….12  DEPARTURE……..+5
TOTAL COOLING UNITS FOR THE MONTH……………135  DEPARTURE……..+8
TOTAL COOLING UNITS FOR THE SEASON…………..646  DEPARTURE……+132
TOTAL COOLING UNITS LAST SEASON TO DATE………634  DEPARTURE…….+12

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)………..41 NE   @   08:13 P.M.
VECTOR #1 (1-Sec)……….43 NE   @   08:13 P.M.
VECTOR #2 (1-Sec)……….41 NE   @   08:13 P.M.
DAVIS #1……………….40 NE   @   08:13 P.M.
DAVIS #2 ………………39 ENE  @   08:13 P.M.
RMY #1 (Instantaneous)…..42 NE   @   08:13 P.M.
RMY #2 (Instantaneous)…..43 NE   @   08:13 P.M.
MERLIN…………………39 NE
RICHARDS (C5C) (Inst)……40      @   08:13 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………26 NE   @   08:14 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..26      @   08:14 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..28      @   08:14 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………27 NE   @   08:14 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………28 NE   @   08:14 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..25 NE   @   08:14 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..27 NE   @   08:14 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………25      @   08:14 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..10.6 SW [255 total miles] VECTOR #1………………10.8
VECTOR #2………………11.2
DAVIS #1……………….10.6 SSW
DAVIS #2……………….11.0 SW
RMY #1…………………10.6 SW
RMY #2…………………11.2 SSW
RICHARDS (C5C)………….10.3

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.19 DEPARTURE…..+0.07
TOTAL PRECIPITATION FOR THE MONTH…………..1.31 DEPARTURE…..-0.90
TOTAL PRECIPITATION FOR THE YEAR (2025)…….30.76 DEPARTURE…..-2.15

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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/…/..            35 NE  VEC1 34 NE  RMY 36 TSTM
8/15  75/63/69/-3/0.00/…/..            29 NE  VEC1 29 ENE RMY 31
8/16  86/62/74/+2/0.00/…/..            23 S   VEC1 24 S   RMY 23
8/17  89/64/77/+5/0.19/…/..            41 NE  VEC1 43 NE  RMY 42 TSTM

8/18 The low since midnight is 59F, the daily normal low is 63F.

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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 18
HIGH 93F IN 2002
LOW 49F IN 1918, 1941
PRECIP 4.64 INCHES IN 1955 [DIANE] PEAK GUST 46 MPH WNW IN 2007

RECORDS FOR AUGUST 19
HIGH 92F IN 2019
LOW 48F IN 1958
PRECIP 8.07 INCHES IN 1955 [DIANE – RECORD FOR MONTH] PEAK GUST 78 MPH ENE IN 1991 – HURRICANE BOB

TODAY’S REPORT PREPARED BY: MFD/JN