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Friday, September 4, 2026

September 4, 2026

BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA FRIDAY, SEPTEMBER 4, 2026 ALL TIMES ARE…

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

FRIDAY, SEPTEMBER 4, 2026
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0513E
SUNSET:  1813E

EARLY MORNING FOG AND RARE UNDERCAST AT BLUE HILL WITH CLEARING
AND ABOVE NORMAL TEMPERATURES….

Skies today were quite interesting! We started this morning with
a rare undercast condition, where all the fog was located near the
surface and plenty of blue sky could be observed above. It is a
phenomenon that happens only a handful of times and has to have
the right conditions to materialize. Photos are on our socials!

After the fog lifted in the area, we had a few cumulus and scattered
altocumulus by mid morning, with increasing clouds by early
afternoon, as temperatures climbed.

Temperatures only dipped to around 63F this morning before a rapid
increase with mostly clear skies. Temperatures have made it to the
lower 80’s by the afternoon. Dew points have been sticky for yet
another day, with levels hovering in the mid to upper 60’s during
the day.

Winds have been light with a mostly northwest to north-northwest
flow for much of the day. The average speed for the day so far
is only around 7mph, but the wind has picked up slightly by the
late morning hours. The peak gust for the day so far is 20mph,
which occurred just before 12:31 this afternoon.

Visibility was only around a mile this morning due to the unique
undercast conditions. Once the fog lifted, visibility improved to
around 50 miles by the early afternoon.

The maximum temperature so far today is 83F, which is 6 degrees
above the normal high of 77F. The minimum temperature since
midnight is 63F, which is 4 degrees below the normal low of 59F.

————————————————————–

Today’s Observations:

7 A.M.
Weather: Overcast, undercast, few altocumulus SSE-WSW
Temperature: 67F; Dew Point: 67F; Relative Humidity: 100%
Wind: NNW @ 6 kts, wind light
Sea-level pressure: 1011.1 mb; 29.86 in. Hg: rising, then more slowly
Visibility: 1 mile, fog
6-hr Max temp: 67F
6-hr Min temp: 63F
24-hr Precip: Trace
BHO SA 1155 /// OVC 1F 111/67/67/3406/986/ UNDERCAST ALQDS FEW AC
SSE-WSW VSBY HIER ABV UNDERCAST WND LGT/ 8//// 51008 70000
10067 20063

10 A.M.
Weather: Scattered altocumulus, few cumulus
Temperature: 78F; Dew Point: 66F; Relative Humidity: 67%
Wind: NW @ 7 kts
Sea-level pressure: 1010.7 mb; 29.85 in. Hg: falling, then more rapidly
Visibility: 40 miles
3-hr Precip: 0.00 inches
BHO SA 1455 85 SCT 40 107/78/66/3207/985/ 8/250 58004

1 P.M.
Weather: Broken cumulus broken cirrus
Temperature: 83F; Dew Point: 63F; Relative Humidity: 51%
Wind: NW @ 7 kts
Sea-level pressure: 1009.5 mb; 29.81 in. Hg: falling, then more slowly
Visibility: 50 miles
6-hr Max temp: 83F
6-hr Min temp: 67F
6-hr Precip: 0.00 inches
BHO SA 1755 E45 BKN 250 BKN 50 095/83/63/3007/981/ 8/201
56012 10083 20067

————————————————————–

SUMMARY FOR THURSDAY, SEPTEMBER 3, 2026

TEMPERATURE (DEGREES F)
MAX…….74   NORMAL…..77
MIN…….60   NORMAL…..60
MEAN……67   NORMAL…..68

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-1
TOTAL DEPARTURE FOR THE MONTH (SEP)………………….-9 [-2.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2026 THRU JUN 2027)
TOTAL HEATING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-1
TOTAL HEATING UNITS FOR THE MONTH (SEP)………..2  DEPARTURE……..-1
TOTAL HEATING UNITS FOR THE SEASON…………….5  DEPARTURE…….-16
TOTAL HEATING UNITS LAST SEASON TO DATE……….21  DEPARTURE…….-16

COOLING DEGREE DAYS (SEASON: JAN 2026 THRU DEC 2026)
TOTAL COOLING UNITS FOR YESTERDAY……………..2  DEPARTURE……..-2
TOTAL COOLING UNITS FOR THE MONTH (SEP)………..4  DEPARTURE…….-10
TOTAL COOLING UNITS FOR THE SEASON…………..758  DEPARTURE……+148
TOTAL COOLING UNITS LAST SEASON TO DATE………678  DEPARTURE…….+80

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 *=Last of multiple occurrences

F420C (Official)………..24 SSE  @   03:07 A.M.
VECTOR #1 (1-Sec)……….24 SSE  @   03:06 A.M.
VECTOR #2 (1-Sec)……….25 S    @   05:53 A.M.
DAVIS #1……………….22 SSE  @   03:07 A.M.
DAVIS #2 ………………27 S    @   05:41 A.M.
RMY #1 (Instantaneous)…..23 SSE  @   03:06 A.M.
RMY #2 (Instantaneous)…..25 S    @   05:53 A.M.
MERLIN………………….M
RICHARDS (C5C) (Inst)……24 SSE  @   03:06 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………16 SE   @   03:51 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..16 SSE  @   03:48 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..18 SE   @   03:51 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 SSE  @   03:45 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………18 S    @   06:02 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..16 SSE  @   03:47 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..18 SE   @   03:51 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………16 SSE  @   03:45 A.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..6.9 SE [166 total miles] VECTOR #1………………7.4
VECTOR #2………………7.6
DAVIS #1……………….7.0 SSE
DAVIS #2…………………M
RMY #1…………………7.3 SSE
RMY #2…………………7.5 SSE
RICHARDS (C5C)………….7.7

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.12
TOTAL PRECIPITATION FOR THE MONTH (SEP)……..0.66 DEPARTURE…..+0.32
TOTAL PRECIPITATION FOR THE YEAR (2026)…….26.65 DEPARTURE…..-8.30

————————————————————–

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  69/57/63/-6/0.21/…/..             15 SSW VEC1 15 E   RMY 14
9/2  76/58/67/-2/0.00/…/..             21 ESE VEC1 21 ESE RMY 20
9/3  74/60/67/-1/0.45/…/..             24 SSE VEC1 24 SSE RMY 23

9/4 The low since midnight is 63F, the daily normal low is 59F.

————————————————————–

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 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: Amanda Joly

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Blue Hill Observatory & Science Center · Legal

Data Use & Privacy Policy

Please read the full Policy before accessing Observatory data · Effective January 1, 2025

Notice: By accessing, downloading, or using any Blue Hill Observatory data or services, you unconditionally accept and agree to be bound by this Policy in its entirety. If you do not agree, you may not access or use Observatory data.
Effective January 1, 2025 · Milton, Massachusetts · bluehill.org
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