Thursday, September 25, 2025

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

THURSDAY, SEPTEMBER 25, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0535E
SUNSET:  1736E

ANOTHER OVERCAST DAY WITH MUCH NEEDED RAINFALL TODAY….

Rain started early this morning with a period of downpours
between 8-9am this morning dropping a very healthy dose of
water to the summit. 0.25″ of rain was measured through 7am,
but an additional 0.93″ fell between 7am and 10am with most
of that falling within about 90 minutes between 7:30 and 9am.
A thunderstorm rolled through between 12-1pm bringing another
downpour to the Hill and an additional 0.26″ of rain. Since
7am we’ve received 1.19″ of rain, but for the 2 days the
total rainfall is 1.56″ through 1pm today.

Temperatures are still on the coolish side, but with the high
humidity levels, it feels rather “warm” out there today.
Readings have been gradually rising from the low to mid 60s
early this morning to around 70 by early this afternoon. Dew
point values are keeping pace with the temperature, so upper
60s to 70F feels quite humid.

The wind has been fairly steady again today, gradually veering
from an easterly direction to more of a southerly direction.
The average speed for the day so far is around 9mph. The peak
gust is 22mph so far, which occurred around 11:30am this
morning.

Visibility has been quite limited today since we’ve been in
the clouds all day. The view has generally been between 1/8th
and 1/4th of a mile.

The maximum temperature so far today is 70F degrees, which is
1 degree above the normal high of 69F. The minimum temperature
since midnight is 62F degrees, which is 10 degrees above the
normal low of 52F.

————————————————————–

Today’s Observations:

7 A.M.
Weather: Sky obscured, vertical visibility 200ft, light rain
Temperature: 63F; Dew Point: 63F; Relative Humidity: 100%
Wind: ESE @ 7 kts
Sea-level pressure: 1017.9 mb; 30.06 in. Hg: falling, then more slowly
Visibility: 1/8 mile, fog
6-hr Max temp: 63F
6-hr Min temp: 62F
24-hr Precip: 0.25 inches
BHO SA 1155 X W2 1/8R-F 179/63/63/1207/006/ 8//// 56012 6018/
70025 10063 20062

10 A.M.
Weather: Sky obscured, vertical visibility 200ft
Temperature: 67F; Dew Point: 67F; Relative Humidity: 100%
Wind: SSE @ 10 kts
Sea-level pressure: 1016.4 mb; 30.01 in. Hg: steady, then falling
Visibility: 1/4 mile, fog
3-hr Precip: 0.93 inches
BHO SA 1455 X W2 1/4F 164/67/67/1510/001/ R-B03E27B33E50/ 8////
58015 6093/

1 P.M.
Weather: Sky obscured, vertical visibility 200ft, light rain showers
Temperature: 70F Dew Point: 70F; Relative Humidity: 100%
Wind: S @ 8 kts
Sea-level pressure: 1013.2 mb; 29.92 in. Hg: falling, then more rapidly
Visibility: 1/4 mile, fog
6-hr Max temp: 70F
6-hr Min temp: 63F
6-hr Precip: 1.19 inches
BHO SA 1755 X W2 1/4RW-F 132/70/70/1708/992/ RW-B06 TB24E39/
8//// 58032 6119/ 10070 20063

————————————————————–

SUMMARY FOR WEDNESDAY, SEPTEMBER 24, 2025

TEMPERATURE (DEGREES F)
MAX…….64   NORMAL…..70
MIN…….61   NORMAL…..53
MEAN……63   NORMAL…..61

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+2
TOTAL DEPARTURE FOR THE MONTH……………………….-8 [-0.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..2  DEPARTURE……..-3
TOTAL HEATING UNITS FOR THE MONTH…………….41  DEPARTURE…….-21
TOTAL HEATING UNITS FOR THE SEASON……………61  DEPARTURE…….-19
TOTAL HEATING UNITS LAST SEASON TO DATE……….56  DEPARTURE……..+5

COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH…………….41  DEPARTURE…….-28
TOTAL COOLING UNITS FOR THE SEASON…………..713  DEPARTURE…….+48
TOTAL COOLING UNITS LAST SEASON TO DATE………753  DEPARTURE…….-40

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 E    @   03:38 P.M.
VECTOR #1 (1-Sec)……….21 E    @   04:03 P.M.
VECTOR #2 (1-Sec)……….22 E    @   06:59 P.M.
DAVIS #1……………….21 E    @   03:38 P.M.
DAVIS #2 ………………20 E    @   03:18 P.M.
RMY #1 (Instantaneous)…..22 E    @   03:38 P.M.
RMY #2 (Instantaneous)…..21 E    @   06:59 P.M.
MERLIN…………………20 E
RICHARDS (C5C) (Inst)……21 E    @   03:38 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 E    @   03:10 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..14 E    @   04:03 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..15 ENE  @   03:24 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 E    @   04:05 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 E    @   03:24 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..15 E    @   04:04 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..15 E    @   03:54 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………15 E    @   04:04 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………9.0 E [217 total miles] VECTOR #1……………….8.6
VECTOR #2……………….9.6
DAVIS #1………………..9.8 E
DAVIS #2………………..9.7 E
RMY #1………………….9.2 E
RMY #2………………….9.5 ENE
RICHARDS (C5C)…………..9.5

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.25 DEPARTURE…..+0.11
TOTAL PRECIPITATION FOR THE MONTH…………..2.95 DEPARTURE…..-0.20
TOTAL PRECIPITATION FOR THE YEAR (2025)…….34.28 DEPARTURE…..-3.48

————————————————————–

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 The low since midnight is 62F, the daily normal low is 52F.

————————————————————–

SEPTEMBER DAILY RECORDS TO DATE

NONE.

————————————————————–

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)

RECORDS FOR SEPTEMBER 25
HIGH 87F IN 1970
LOW 31F IN 1950
PRECIP 2.68 INCHES IN 1961
PEAK GUST 63 MPH SSW IN 1991

RECORDS FOR SEPTEMBER 26
HIGH 91F IN 2007
LOW 36F IN 1905,1922,1978
PRECIP 3.84 INCHES IN 1888
PEAK GUST 54e MPH S IN 1977

TODAY’S REPORT PREPARED BY: Matt Douglas/Amanda Joly