Monday, September 29, 2025

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

MONDAY SEPTEMBER 29, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0539E
SUNSET:  1729E

ABUNDANT SUNSHINE THROUGH THE MORNING, THEN INCREASING HIGH
CLOUDS THIS AFTERNOON….

The day started off brilliantly with clear skies and plenty
of bright sunshine. As we approached the early afternoon
however, cirrus clouds have overspread the area as a system
well to our south tries to push up the coast. As it looks
right now, only clouds from this system will impact the area
through tomorrow.

Temperatures are still on the warm side today, but not quite
as warm as the past few days. Readings have reached the mid
to upper 70s early this afternoon. A nice change however is
the lower dew point values today, making the air mass feel a
lot more comfortable than over the weekend. Values have been
mainly in the low 50s, but did drop to the mid 40s for a
time during the late morning period.

The wind was a bit busy during the overnight as a dry front
pushed through the area switching the wind to north. It was
gusty for a time thanks to some cold air advection. The wind
has since diminished quite a bit into early this afternoon
becoming light and variable. The average speed for the day
so far is around 8mph, but it has been generally averaging
around 2-4mph for the past 3 hours or so. The peak gust for
the day is 18mph, which occurred just after midnight.

Visibility has been decent for the most part, holding at
around 60 miles all day.

The maximum temperature so far today is 78F degrees, which is
10 degrees above the normal high of 68F. The minimum temperature
since midnight is 58F degrees, which is 7 degrees above the
normal low of 51F.

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Today’s Observations:

7 A.M.
Weather: Clear, few altocumulus distant S-SW, few cirrus distant
ESE-S-WSW
Temperature: 62F; Dew Point: 50F; Relative Humidity: 64%
Wind: N @ 9 kts
Sea-level pressure: 1024.6 mb; 30.26 in. Hg: rising unsteadily
Visibility: 60 miles
6-hr Max temp: 65F
6-hr Min temp: 58F
24-hr Precip: 0.00 inches
BHO SA 1155 CLR 60 246/62/50/3609/026/ FEW AC DSNT S-SW
FEW CI DSNT ESE-S-WSW/ 8/051 52013 10065 20058

10 A.M.
Weather: Clear, few cirrus distant SE-WSW
Temperature: 74F; Dew Point: 51F; Relative Humidity: 44%
Wind: E @ 2 kts, wind light and variable
Sea-level pressure: 1025.0 mb; 30.27 in. Hg: rising, then falling
Visibility: 60 miles
3-hr Precip: 0.00 inches
BHO SA 1455 CLR 60 250/74/51/0802/027/ FEW CI DSNT SE-WSW
WND L/V/ 8/004 50004

1 P.M.
Weather: Broken cirrus
Temperature: 77F Dew Point: 51F; Relative Humidity: 40%
Wind: W @ 2 kts, wind light and variable
Sea-level pressure: 1023.7 mb; 30.23 in. Hg: falling, then more rapidly
Visibility: 60 miles
6-hr Max temp: 78F
6-hr Min temp: 62F
6-hr Precip: 0.00 inches
BHO SA 1755 E250 BKN 60 237/77/51/2802/023/ WND L/V/ 8/004 58013
10078 20062

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SUMMARY FOR SUNDAY, SEPTEMBER 28, 2025

TEMPERATURE (DEGREES F)
MAX…….81   NORMAL…..68
MIN…….63   NORMAL…..51
MEAN……72   NORMAL…..59

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………+13
TOTAL DEPARTURE FOR THE MONTH………………………+32 [+1.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-6
TOTAL HEATING UNITS FOR THE MONTH…………….41  DEPARTURE…….-45
TOTAL HEATING UNITS FOR THE SEASON……………61  DEPARTURE…….-43
TOTAL HEATING UNITS LAST SEASON TO DATE……….63  DEPARTURE……..-2

COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..7  DEPARTURE……..+6
TOTAL COOLING UNITS FOR THE MONTH…………….61  DEPARTURE…….-12
TOTAL COOLING UNITS FOR THE SEASON…………..733  DEPARTURE…….+64
TOTAL COOLING UNITS LAST SEASON TO DATE………757  DEPARTURE…….-24

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 N    @   10:56 P.M.
VECTOR #1 (1-Sec)……….22 N    @   10:35 P.M.
VECTOR #2 (1-Sec)……….23 N    @   10:35 P.M.
DAVIS #1……………….20 N    @   10:35 P.M.
DAVIS #2 ………………20 NNE  @   10:35 P.M.
RMY #1 (Instantaneous)…..22 SW   @   10:24 A.M.
RMY #2 (Instantaneous)…..22 N    @   10:35 P.M.
MERLIN…………………20 N
RICHARDS (C5C) (Inst)……21 SW   @   10:50 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 N    @   10:38 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..15 SW   @   10:24 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..15 SW   @   10:50 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………14 SW   @   10:50 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 SW   @   10:50 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..14 SW   @   10:50 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..15 SW   @   10:50 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………14 SW   @   10:50 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………9.1 WSW [218 total miles] VECTOR #1……………….9.4
VECTOR #2……………….9.7
DAVIS #1………………..9.2 SW
DAVIS #2………………..9.4 WSW
RMY #1………………….9.3 SW
RMY #2………………….9.7 SW
RICHARDS (C5C)…………..9.3

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.15
TOTAL PRECIPITATION FOR THE MONTH…………..4.49 DEPARTURE…..+0.74
TOTAL PRECIPITATION FOR THE YEAR (2025)…….35.82 DEPARTURE…..-2.54

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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   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/+3/0.00/572/76            15 NE  VEC1 15 SW  RMY 15
9/15  72/57/65/0/0.00/689/92             20 N   VEC1 19 N   RMY 18
9/16  71/55/63/-1/0.00/403/54            20 E   VEC1 19 ESE RMY 19
9/17  71/55/63/-1/T/424/57               22 E   VEC1 22 E   RMY 21
9/18  75/61/68/+5/0.44/252/34            20 S   VEC1 20 S   RMY 20 TSTM
9/19  80/57/69/+6/0.00/715/97            24 N   VEC1 24 N   RMY 23
9/20  67/51/59/-4/0.00/705/96            20 SE  VEC1 19 SE  RMY 18
9/21  68/52/60/-2/0.00/593/81            18 ESE VEC1 19 SE  RMY 19
9/22  73/53/63/+1/0.00/620/85            20 SSW VEC1 20 SW  RMY 21
9/23  78/57/68/+6/0.00/305/42            25 SW  VEC1 25 SW  RMY 26
9/24  64/61/63/+2/0.19/000/00            21 E   VEC1 21 E   RMY 22
9/25  70/62/66/+5/1.67/000/00            35 SSW VEC1 35 SSW RMY 35 TSTM
9/26  80/63/72/+12/0.00/…/..           24 NW  VEC1 23 WNW RMY 27
9/27  80/59/70/+10/0.00/…/..           20 S   VEC1 20 S   RMY 18
9/28  81/63/72/+13/0.05/…/..           22 N   VEC1 22 N   RMY 22

9/29 The low since midnight is 58F, the daily normal low is 51F.

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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 29
HIGH 85F IN 1952
LOW 28F IN 1914 (SEPTEMBER MINIMUM RECORD)
PRECIP 2.61 INCHES IN 1907
PEAK GUST 62 MPH S IN 2005

RECORDS FOR SEPTEMBER 30
HIGH 84F IN 1986
LOW 31F IN 1992
PRECIP 2.44 INCHES IN 2015
PEAK GUST 71 MPH S IN 2020

TODAY’S REPORT PREPARED BY: Matt Douglas