Sunday, August 17, 2025
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
SUNDAY, AUGUST 17, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0454E
SUNSET: 1842E
EARLY MORNING CLOUDS AND FOG BURN OFF TO SUNSHINE; HOT AND HUMID….
We started the day with overcast skies and some fog drifting
over the Hill, but the clouds and fog burned off by mid morning
with plenty of sunshine taking over. Once the sun returned, the
temperatures started rising rapidly.
Temperatures have reached the mid to upper 80s by early this
afternoon. The one thing that’s different from yesterday is the
higher humidity levels. Dew point readings have pushed into the
low 70s by late this morning giving us a much more oppressive
feel than yesterday. The combination of the temperature and
dew point is giving us heat index readings into the mid 90s.
The wind has been fairly steady today averaging at around 11mph.
The peak gust so far for the day is 21mph, which occurred after
12:30pm.
Visibility is limited again today, this morning because of fog,
and now due to general haziness. The view has been generally
10-30 miles once the fog burned off.
The maximum temperature so far today is 88F degrees, which is
8 degrees above the normal high of 80F. The minimum temperature
since midnight is 65F degrees, which is 2 degrees above the
normal low of 63F.
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Today’s Observations:
7 A.M.
Weather: Overcast stratus
Temperature: 69F; Dew Point: 68F; Relative Humidity: 94%
Wind: SW @ 9 kts
Sea-level pressure: 1014.5 mb; 29.96 in. Hg: falling, then more rapidly
Visibility: 10 miles, 15 miles NE, 20 miles E-SE, thin fog
6-hr Max temp: 69F
6-hr Min temp: 65F
24-hr Precip: 0.00 inches
BHO SA 1155 E6 OVC 10 145/69/68/2309/996/ THN F ALQDS VSBY 15 NE
20 E-SE/ 8/6// 58011 10069 20065
10 A.M.
Weather: Clear, few small cumulus distant ESE-S-W, few cirrus all
quadrants
Temperature: 80F; Dew Point: 72F Relative Humidity: 75%
Wind: SW @ 8G15 kts
Sea-level pressure: 1013.6 mb; 29.93 in. Hg: falling, then more slowly
Visibility: 20 miles, hazy
3-hr Precip: 0.00 inches
BHO SA 1455 CLR 20 136/80/72/2208G15/993/ FEW SML CU DSNT ESE-S-W
FEW CI ALQDS HAZY/ 8/101 56009
1 P.M.
Weather: Broken cumulus, broken cirrus, moderate cumulus all quadrants
Temperature: 88F Dew Point: 71F; Relative Humidity: 58%
Wind: WSW @ 9G16 kts
Sea-level pressure: 1012.0 mb; 29.88 in. Hg: falling, then more rapidly
Visibility: 30 miles, hazy
6-hr Max temp: 88F
6-hr Min temp: 69F
6-hr Precip: 0.00 inches
BHO SA 1755 E40 BKN 250 BKN 30 120/88/71/2509G16/988/
MDT CU ALQDS HAZY/ 8/201 58016 10088 20069
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SUMMARY FOR SATURDAY, AUGUST 16, 2025
TEMPERATURE (DEGREES F)
MAX…….86 NORMAL…..80
MIN…….62 NORMAL…..63
MEAN……74 NORMAL…..72
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+2
TOTAL DEPARTURE FOR THE MONTH……………………….+2 [-0.1 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……………..9 DEPARTURE……..+2
TOTAL COOLING UNITS FOR THE MONTH……………123 DEPARTURE……..+3
TOTAL COOLING UNITS FOR THE SEASON…………..634 DEPARTURE……+127
TOTAL COOLING UNITS LAST SEASON TO DATE………631 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)………..23 S @ 07:23 P.M.
VECTOR #1 (1-Sec)……….24 S @ 07:22 P.M.
VECTOR #2 (1-Sec)……….22 S @ 06:49 P.M.
DAVIS #1……………….24 S @ 06:57 P.M.
DAVIS #2 ………………26 S @ 06:49 P.M.
RMY #1 (Instantaneous)…..23 SSW @ 07:37 P.M.
RMY #2 (Instantaneous)…..23 S @ 06:59 P.M.
MERLIN…………………21 S
RICHARDS (C5C) (Inst)……21 @ 07:37 P.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 SSW @ 07:24 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..16 @ 07:38 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..17 @ 07:38 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 S @ 07:38 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………19 S @ 06:03 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..15 SSW @ 07:38 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..17 S @ 07:38 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………15 @ 07:38 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………7.3 SSW [174 total miles]
VECTOR #1……………….7.9
VECTOR #2……………….8.2
DAVIS #1………………..7.5 SSW
DAVIS #2………………..8.1 SSW
RMY #1………………….7.7 SSW
RMY #2………………….8.3 SSW
RICHARDS (C5C)…………..8.0
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.13
TOTAL PRECIPITATION FOR THE MONTH…………..1.12 DEPARTURE…..-0.97
TOTAL PRECIPITATION FOR THE YEAR (2025)…….30.57 DEPARTURE…..-2.22
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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 The low since midnight is 65F, 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 17
HIGH 97F IN 1944
LOW 48F IN 1902
PRECIP 2.17 INCHES IN 1998
PEAK GUST 50e MPH SSW IN 1952, 50 MPH WNW IN 1962
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
TODAY’S REPORT PREPARED BY: MFD
