Thursday, September 4, 2025

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

THURSDAY, SEPTEMBER 4, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0513E
SUNSET:  1813E

SUNSHINE WITH WARM TEMPERATURES AND STILL COMFORTABLE HUMIDITY….

The day started with some fog very early this morning, otherwise
sunshine has been the theme so far today. As is usually the case
on days like this, diurnal cumulus have once again popped up
dotting the sky. All in all it’s been a very nice start to
September.

Temperatures are quite pleasant once again for this time of year
with readings reaching the upper 70s by early this afternoon.
This is just a tad above where we should be for early September.
The dew point continues to run in the comfortable range with
values generally in the mid to upper 50s.

The wind has once again been mainly on the light side, although
it has attempted to pick up a bit at times early this afternoon.
Either way, the average speed has been around 8mph for the day
so far. What wind there is has been generally out of the south-
southwest to south. The peak gust for the day so far is 18mph,
which occurred right around 12:30pm.

Visibility is a bit more limited today than yesterday, with the
view starting at around 40 miles early this morning, but
recovering to around 50 miles by early this afternoon.

The maximum temperature so far today is 79F degrees, which is
2 degrees above the normal high of 77F. The minimum temperature
since midnight is 56 degrees, which is 3 degrees below the normal
low of 59F.

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Today’s Observations:

7 A.M.
Weather: Clear, stratus layer distant ESE-SW, few cirrus distant
E-ESE
Temperature: 61F; Dew Point: 59F; Relative Humidity: 93%
Wind: SW @ 6 kts, wind light
Sea-level pressure: 1014.9 mb; 29.97 in. Hg: rising, then more slowly
Visibility: 40 miles, thin fog
6-hr Max temp: 61F
6-hr Min temp: 56F
24-hr Precip: 0.00 inches
BHO SA 1155 CLR 40 149/61/59/2206/997/ ST LYR DSNT ESE-SW FEW CI
DSNT E-ESE THN F ALQDS WND LGT VSBY 20 ESE-SW/ 8/601 51010 10061
20056

10 A.M.
Weather: Clear, few cumulus distant E-S-W-NW
Temperature: 72F; Dew Point: 58F; Relative Humidity: 60%
Wind: S @ 6 kts, wind light
Sea-level pressure: 1014.9 mb; 29.97 in. Hg: rising, then falling
Visibility: 50 miles
3-hr Precip: 0.00 inches
BHO SA 1455 CLR 50 149/72/58/1706/997/ FEW CU DSNT E-S-W-NW
WND LGT/ 8/200 50000

1 P.M.
Weather: Broken cumulus, broken cirrus
Temperature: 77F Dew Point: 57F; Relative Humidity: 49%
Wind: SSW @ 7 kts, wind SSW variable W
Sea-level pressure: 1013.7 mb; 29.93 in. Hg: falling, then more rapidly
Visibility: 50 miles
6-hr Max temp: 79F
6-hr Min temp: 61F
6-hr Precip: 0.00 inches
BHO SA 1755 E35 BKN 250 BKN 50 137/77/57/2007/993/ WND 19V26/
8/201 58012 10079 20061

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SUMMARY FOR WEDNESDAY, SEPTEMBER 3, 2025

TEMPERATURE (DEGREES F)
MAX…….78   NORMAL…..77
MIN…….57   NORMAL…..60
MEAN……68   NORMAL…..68

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………..0
TOTAL DEPARTURE FOR THE MONTH……………………….-6 [-2.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-1
TOTAL HEATING UNITS FOR THE MONTH……………..1  DEPARTURE……..-2
TOTAL HEATING UNITS FOR THE SEASON……………21  DEPARTURE………0
TOTAL HEATING UNITS LAST SEASON TO DATE……….14  DEPARTURE……..+7

COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..3  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH……………..6  DEPARTURE……..-8
TOTAL COOLING UNITS FOR THE SEASON…………..678  DEPARTURE…….+68
TOTAL COOLING UNITS LAST SEASON TO DATE………707  DEPARTURE…….-29

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)………..21 SSW  @   08:36 P.M.
VECTOR #1 (1-Sec)……….21 SSW  @   07:20 P.M.
VECTOR #2 (1-Sec)……….21 SSW  @   07:20 P.M.
DAVIS #1……………….22 S    @   07:20 P.M.
DAVIS #2 ………………24 S    @   07:20 P.M.
RMY #1 (Instantaneous)…..21 SSW  @   07:24 P.M.
RMY #2 (Instantaneous)…..22 SSW  @   07:20 P.M.
MERLIN…………………19 SSW
RICHARDS (C5C) (Inst)……20 SSW  @   07:24 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 SSW  @   08:37 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..15 SSW  @   07:25 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..16 SSW  @   07:25 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………15 S    @   08:15 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………16 S    @   07:21 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..14 SSW  @   07:25 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..16 SSW  @   07:25 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………14 SSW  @   08:14 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………7.6 SSW [183 total miles] VECTOR #1……………….8.1
VECTOR #2……………….8.6
DAVIS #1………………..7.8 SSW
DAVIS #2………………..8.2 SW
RMY #1………………….7.8 SW
RMY #2………………….8.6 SSW
RICHARDS (C5C)…………..8.1

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.11
TOTAL PRECIPITATION FOR THE MONTH…………..0.00 DEPARTURE…..-0.34
TOTAL PRECIPITATION FOR THE YEAR (2025)…….31.33 DEPARTURE…..-3.62

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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 The low since midnight is 56F, the daily normal low is 59F.

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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 4
HIGH 90F IN 1953, 1973
LOW 46F IN 1987
PRECIP 3.22 INCHES IN 1922
PEAK GUST 47 MPH SE IN 1966

RECORDS FOR SEPTEMBER 5
HIGH 90F IN 1971
LOW 45F IN 1906
PRECIP 1.37 INCHES IN 1907
PEAK GUST 46 MPH NW IN 1994

TODAY’S REPORT PREPARED BY: Matt Douglas