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BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
SUNDAY, SEPTEMBER 20, 2026
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0529E
SUNSET: 1745E
OVERCAST SKIES, LIGHT DRIZZLE AND COOLER TEMPERATURES TO END
THE FINAL WEEKEND OF ASTRONOMICAL SUMMER….
The tiniest bit of sunlight and color was observed this morning
just after sunrise. After that, cloud cover continued to increase
and we’ve been under overcast skies since around 8am EST. Some light
drizzle has been observed throughout the day, but as of 1pm EST
we have only received a trace of precipitation. The rain is in the
area though and more than likely we should receive at least something
measurable by the day’s end.
Temperatures have struggled to increase much today, mostly due to
the overcast conditions and the arrival of the low pressure system
into the region. Temperatures overnight dipped down to 51F and for
much of the observational period were in the mid to upper 50s. Dew
points have stayed in the lower 50s which is a few degrees warmer
than yesterday’s dew point values. Southeast flow has brought more
humid air over the area so it’s felt a little more sticky compared
to yesterday.
Winds have continued to trend on the light side, with winds mostly
out of the southeast and south-southeast today. The average speed
for the day so far is around 8mph. The peak gust for the day so far
is 20mph, which occurred just after 1:30pm this afternoon.
Visibility was decent this morning, with around 70 miles. By the
mid morning hours, however, visibility was cut to 35 miles which
is where it remained through the early afternoon.
The maximum temperature so far today is 61F, which is 10 degrees
below the normal high of 71F. The minimum temperature since
midnight is 51F, which is 3 degrees below the normal low of 54F.
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Today’s Observations:
7 A.M.
Weather: Overcast altocumulus, few stratocumulus offshore distant
NNE-ESE, few breaks in overcast all quadrants
Temperature: 54F; Dew Point: 50F; Relative Humidity: 86%
Wind: SSE @ 6 kts, wind light
Sea-level pressure: 1021.3 mb; 30.16 in. Hg: rising, then falling
Visibility: 70 miles
6-hr Max temp: 54F
6-hr Min temp: 52F
24-hr Precip: 0.00 inches
BHO SA 1155 E120 OVC 70 213/54/50/1506/016/ FEW SC OFFSHR DSNT NNE-ESE
FEW BINOVC ALQDS WND LGT/ 8/55/ 55005 10054 20052
10 A.M.
Weather: Light drizzle, overcast altostratus, few stratocumulus all
quadrants
Temperature: 59F; Dew Point: 52F; Relative Humidity: 79%
Wind: S @ 5 kts, wind light
Sea-level pressure: 1021.0 mb; 30.15 in. Hg: rising, then falling
Visibility: 35 miles
3-hr Precip: Trace
BHO SA 1455 E85 OVC 35L- 210/59/52/1705/015/ FEW SC ALQDS PCPN VRY LGT
WND LGT/ 8/55/ 58003 6000/
1 P.M.
Weather: Broken stratocumulus, overcast altostratus
Temperature: 59F; Dew Point: 54F; Relative Humidity: 82%
Wind: SSE @ 7 kts
Sea-level pressure: 1018.9 mb; 30.09 in. Hg: falling steadily
Visibility: 35 miles
6-hr Max temp: 61F
6-hr Min temp: 54F
6-hr Precip: Trace
BHO SA 1755 E40 BKN 90 OVC 35 189/59/54/1507/009/ 8/55/ 57021 6000/
10061 20054
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SUMMARY FOR SATURDAY, SEPTEMBER 19, 2026
TEMPERATURE (DEGREES F)
MAX…….63 NORMAL…..72
MIN…….50 NORMAL…..55
MEAN……57 NORMAL…..63
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-6
TOTAL DEPARTURE FOR THE MONTH (SEP)………………….+4 [0.0 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2026 THRU JUN 2027)
TOTAL HEATING UNITS FOR YESTERDAY……………..8 DEPARTURE……..+4
TOTAL HEATING UNITS FOR THE MONTH (SEP)……….24 DEPARTURE…….-15
TOTAL HEATING UNITS FOR THE SEASON……………27 DEPARTURE…….-30
TOTAL HEATING UNITS LAST SEASON TO DATE……….46 DEPARTURE…….-19
COOLING DEGREE DAYS (SEASON: JAN 2026 THRU DEC 2026)
TOTAL COOLING UNITS FOR YESTERDAY……………..0 DEPARTURE……..-2
TOTAL COOLING UNITS FOR THE MONTH (SEP)……….51 DEPARTURE…….-10
TOTAL COOLING UNITS FOR THE SEASON…………..805 DEPARTURE……+148
TOTAL COOLING UNITS LAST SEASON TO DATE………710 DEPARTURE…….+95
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)………..21 N @ 12:05 A.M.
VECTOR #1 (1-Sec)……….20 N @ 12:05 A.M.
VECTOR #2 (1-Sec)……….22 N @ 12:01 A.M.
DAVIS #1……………….17 N @ 12:01 A.M.
DAVIS #2 ………………18 N @ 12:01 A.M.
RMY #1 (Instantaneous)…..20 N @ 12:05 A.M.
RMY #2 (Instantaneous)…..20 N @ 12:01 A.M.
MERLIN………………….M
RICHARDS (C5C) (Inst)……19 N @ 12:05 A.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………13 N @ 12:07 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..14 N @ 12:07 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..13 N @ 12:05 A.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………13 N @ 12:06 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………13 NNE @ 12:06 A.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..13 N @ 12:07 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..13 N @ 12:05 A.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………13 N @ 12:07 A.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..7.1 ENE [170 total miles]
VECTOR #1………………7.8
VECTOR #2………………8.2
DAVIS #1……………….7.5 ENE
DAVIS #2…………………M
RMY #1…………………7.8 ENE
RMY #2…………………8.1 ENE
RICHARDS (C5C)………….8.8
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.15
TOTAL PRECIPITATION FOR THE MONTH (SEP)……..2.04 DEPARTURE…..-0.37
TOTAL PRECIPITATION FOR THE YEAR (2026)…….28.03 DEPARTURE…..-8.99
————————————————————–
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/-6/0.21/008/01 15 SSW VEC1 15 E RMY 14
9/2 76/58/67/-2/0.00/393/50 21 ESE VEC1 21 ESE RMY 20
9/3 74/60/67/-1/0.45/196/25 24 SSE VEC1 24 SSE RMY 23
9/4 84/63/74/+6/0.00/624/80 24 NNW VEC1 25 NNW RMY 24
9/5 71/60/66/-2/T/412/53 24 ENE VEC1 24 ENE RMY 25
9/6 69/53/61/-7/0.35/364/47 24 NE VEC1 24 NNE RMY 27
9/7 79/52/66/-1/0.00/732/95 30 NW VEC1 30 NW RMY 30
9/8 80/58/69/+2/0.00/546/71 23 WNW VEC1 22 NNW RMY 24
9/9 80/58/69/+2/0.02/130/17 36 SSW VEC1 36 SSW RMY 36
9/10 84/67/76/+10/T/641/84 44 W VEC1 43 W RMY 47
9/11 77/59/68/+2/0.00/654/86 23 NW VEC1 23 NW RMY 25
9/12 77/55/66/0/0.00/667/88 23 SSW VEC1 23 SSW RMY 22
9/13 67/60/64/-1/0.98/000/00 25 SE VEC1 26 SE RMY 24
9/14 72/53/63/-2/T/572/76 32 NNW VEC1 32 NNW RMY 34
9/15 68/48/58/-7/0.00/727/97 18 S VEC1 18 SE RMY 18
9/16 78/53/66/+2/0.00/522/70 21 SW VEC1 21 WSW RMY 21
9/17 82/63/73/+9/0.03/…/.. 25 SW VEC1 25 SW RMY 27
9/18 79/58/69/+6/T/…/.. 26 N VEC1 26 NNW RMY 27
9/19 63/50/57/-6/0.00/…/.. 21 N VEC1 20 N RMY 20
9/20 The low since midnight is 51F, the daily normal low is 54F.
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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 20
HIGH 90 IN 1983
LOW 34 IN 1979
PRECIP 4.57 INS IN 1899
PEAK GUST 44 MPH NE IN 1972
RECORDS FOR SEPTEMBER 21
HIGH 91 IN 1895
LOW 35 IN 1929, 1956, 1962
PRECIP 5.58 INS IN 1961 (HURRICANE ESTHER; RETURNED AS TS SEPT 25-26TH)
PEAK GUST 186 MPH S IN 1938 (GREAT NEW ENGLAND HURRICANE; CALCULATED GUST, STATION RECORD)
TODAY’S REPORT PREPARED BY: Amanda Joly
