Tuesday, September 9, 2025
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
TUESDAY, SEPTEMBER 9, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0518E
SUNSET: 1804E
MORE SUNSHINE THAN YESTERDAY; BRISK AND COOL WITH AN ONSHORE WIND….
Today has featured much more sunshine than yesterday. A period
of low ocean clouds did move through during the mid to late
morning period, but they have since dissipated for the most
part.
Temperatures are once again below normal today as readings have
only reached 70F so far. Normal highs should be in the mid 70s
at this time of year. Dew point values, which dropped into the
mid 30s for about an hour during the wee hours as we briefly
ended up below the inversion, has otherwise been mainly in the
low to mid 50s today. Either way, very comfortable air is in
place.
The wind started the day on the light side, but increased during
the morning as high pressure crested to our north. A generally
northeast flow has been averaging at around 8mph for the day so
far. The peak gust for the day is 21mph, which around 11:45am
this morning.
Visibility has been quite decent today, ranging from around 50
miles early this morning up to around 70 miles by early this
afternoon.
The maximum temperature so far today is 70F degrees, which is
6 degrees below the normal high of 76F. The minimum temperature
since midnight is 53F degrees, which is 5 degrees below the
normal low of 58F.
————————————————————–
Today’s Observations:
7 A.M.
Weather: Scattered cirrus, few stratocumulus distant SSE-S
Temperature: 56F; Dew Point: 52F; Relative Humidity: 86%
Wind: NE @ 12 kts
Sea-level pressure: 1029.6 mb; 30.40 in. Hg: rising, then more slowly
Visibility: 50 miles
6-hr Max temp: 58F
6-hr Min temp: 53F
24-hr Precip: 0.00 inches
BHO SA 1155 250 SCT 50 296/56/52/0412/040/ FEW SC DSNT SSE-S
PTCHY GF ALQDS/ 8/501 51016 10058 20053
10 A.M.
Weather: Broken stratocumulus, broken cirrus
Temperature: 66F; Dew Point: 53F; Relative Humidity: 64%
Wind: E @ 8G15 kts
Sea-level pressure: 1029.9 mb; 30.41 in. Hg: rising, then more slowly
Visibility: 60 miles
3-hr Precip: 0.00 inches
BHO SA 1455 E30 BKN 250 BKN 60 299/66/53/0808G15/041/ 8/501 51003
1 P.M.
Weather: Scattered cirrus, few stratocumulus all quadrants
Temperature: 69F Dew Point: 51F; Relative Humidity: 53%
Wind: E @ 11G16 kts
Sea-level pressure: 1029.1 mb; 30.39 in. Hg: steady, then falling
Visibility: 70 miles
6-hr Max temp: 70F
6-hr Min temp: 56F
6-hr Precip: 0.00 inches
BHO SA 1755 250 SCT 70 291/69/51/0811G16/039/ FEW SC ALQDS/
8/501 58008 10070 20056
————————————————————–
SUMMARY FOR MONDAY, SEPTEMBER 8, 2025
TEMPERATURE (DEGREES F)
MAX…….68 NORMAL…..76
MIN…….49 NORMAL…..58
MEAN……59 NORMAL…..67
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-8
TOTAL DEPARTURE FOR THE MONTH……………………….-9 [-1.3 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..6 DEPARTURE……..+4
TOTAL HEATING UNITS FOR THE MONTH…………….12 DEPARTURE……..+2
TOTAL HEATING UNITS FOR THE SEASON……………32 DEPARTURE……..+4
TOTAL HEATING UNITS LAST SEASON TO DATE……….19 DEPARTURE…….+13
COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..0 DEPARTURE……..-4
TOTAL COOLING UNITS FOR THE MONTH…………….27 DEPARTURE……..-6
TOTAL COOLING UNITS FOR THE SEASON…………..699 DEPARTURE…….+70
TOTAL COOLING UNITS LAST SEASON TO DATE………716 DEPARTURE…….-17
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 NW @ 03:31 A.M.
VECTOR #1 (1-Sec)……….21 NW @ 03:31 A.M.
VECTOR #2 (1-Sec)……….21 NW @ 03:31 A.M.
DAVIS #1……………….21 NW @ 03:31 A.M.
DAVIS #2 ………………21 WNW @ 12:28 A.M.
RMY #1 (Instantaneous)…..24 NW @ 03:31 A.M.
RMY #2 (Instantaneous)…..23 WNW @ 01:29 A.M.
MERLIN…………………19 NW
RICHARDS (C5C) (Inst)……22 NW @ 03:31 A.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………15 NW @ 03:34 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..15 NW @ 03:33 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..16 NW @ 12:29 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………15 NW @ 03:33 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 NW @ 12:29 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..15 NW @ 03:33 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..15 NW @ 12:29 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………15 NW @ 03:33 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………7.3 NW [174 total miles]
VECTOR #1……………….7.9
VECTOR #2……………….8.2
DAVIS #1………………..7.6 NW
DAVIS #2………………..7.4 NNW
RMY #1………………….7.6 NW
RMY #2………………….8.0 NW
RICHARDS (C5C)…………..8.2
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.11
TOTAL PRECIPITATION FOR THE MONTH…………..2.14 DEPARTURE…..+1.20
TOTAL PRECIPITATION FOR THE YEAR (2025)…….33.47 DEPARTURE…..-2.08
————————————————————–
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/…/.. 26 SSW VEC1 27 SSW RMY 28
9/5 82/63/73/+5/0.12/…/.. 30 SSW VEC1 31 SSW RMY 33
9/6 84/64/74/+6/1.05/…/.. 55 W VEC1 55 W RMY 57 TSTM
9/7 64/56/60/-7/0.97/…/.. 16 WNW VEC1 16 NNE RMY 15
9/8 68/49/59/-8/0.00/…/.. 21 NW VEC1 21 NW RMY 24
9/9 The low since midnight is 53F, the daily normal low is 58F.
————————————————————–
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 9
HIGH 92F IN 2015
LOW 41F IN 1938
PRECIP 1.97 INCHES IN 1969
PEAK GUST 52 MPH WNW IN 1969, NW IN 1978
RECORDS FOR SEPTEMBER 10
HIGH 90F IN 1931,1989
LOW 41F IN 1956
PRECIP 5.60 INCHES IN 1999 (DAILY RECORD FOR SEPTEMBER)
PEAK GUST 48 MPH NW IN 1972
TODAY’S REPORT PREPARED BY: Matt Douglas
