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Monday, May 11, 2026

May 11, 2026

BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA MONDAY, MAY 11, 2026 ALL TIMES ARE…

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

MONDAY, MAY 11, 2026
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0427E
SUNSET:  1855E

COOLER AND DRIER AIR TODAY FOLLOWING A COLD FRONTAL PASSAGE….

A cold front moved through last evening bringing a few very light
rain showers and a shift in wind direction from the southwest to
the north-northwest. While the front itself came through with
little fanfare, it did bring a pretty significant change to the
air mass over the area. Yesterday’s warm temperatures and higher
dew points have been replaced with cooler and much drier air.

Clouds have been lingering through the day today with some
filtered sunshine at times. All in all it’s a very pleasant day
with near seasonable temperatures and a light breeze.

As mentioned, temperatures are near seasonable levels today with
readings reaching the low 60s by early this afternoon. The dew
point is much lower today than it was yesterday with values
dropping to the low 30s.

Winds have been fairly steady, but fairly light today out of the
north-northwest. The average speed for the day so far is around
9mph. The peak gust so far for the day is 26mph, which occurred
just before 12:30am this morning.

Visibility has been excellent today, even reaching a perfect
90 miles early this morning for a time, but has since slipped
back to around 70-80 miles by early this afternoon.

The maximum temperature so far today is 62F degrees, which is
4 degrees below the normal high of 66F. The minimum temperature
since midnight is 50F degrees, which is 3 degrees above the
normal low of 47F.

————————————————————–

Today’s Observations:

7 A.M.
Weather: Overcast cirrostratus, broken altocumulus, clearing line
distant WSW-NNE
Temperature: 52F; Dew Point: 34F; Relative Humidity: 50%
Wind: NNW @ 6 kts, wind light
Sea-level pressure: 1019.6 mb; 30.11 in. Hg: rising steady
Visibility: 90 miles
6-hr Max temp: 56F
6-hr Min temp: 50F
24-hr Precip: Trace
BHO SA 1155 E80 BKN 200 OVC 90 196/52/34/3306/011/ CLRG LINE DSNT
WSW-NNE WND LGT/ 8/058 52008 6000/ 70000 10056 20050

10 A.M.
Weather: Broken altocumulus/castellanus, broken cirrostratus,
broken cirrus, few cumulus distant W-NNE
Temperature: 58F; Dew Point: 33F; Relative Humidity: 39%
Wind: NNW @ 7 kts
Sea-level pressure: 1019.6 mb; 30.11 in. Hg: falling, then rising
Visibility: 80 miles
3-hr Precip: 0.00 inches
BHO SA 1455 E75 BKN 220 BKN 250 BKN 80 196/53/33/3407/011/
FEW CU DSNT W-NNE/ 8/256 55000

1 P.M.
Weather: Overcast altostratus, few stratocumulus distant WSW-NNE,
few altocumulus distant ESE-SW
Temperature: 59F; Dew Point: 32F; Relative Humidity: 35%
Wind: WNW @ 6 kts, wind light
Sea-level pressure: 1018.2 mb; 30.07 in. Hg: falling, then more slowly
Visibility: 70 miles
6-hr Max temp: 62F
6-hr Min temp: 52F
6-hr Precip: 0.00 inches
BHO SA 1755 E120 OVC 70 182/59/32/3006/007/ FEW SC DSNT WSW-NNE
FEW AC DSNT ESE-SW WND LGT/ 8/57/ 56014 10062 20052

————————————————————–

SUMMARY FOR SUNDAY, MAY 10, 2026

TEMPERATURE (DEGREES F)
MAX…….72   NORMAL…..65
MIN…….49   NORMAL…..47
MEAN……61   NORMAL…..56

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+5
TOTAL DEPARTURE FOR THE MONTH……………………….+5 [ 0.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..4  DEPARTURE……..-6
TOTAL HEATING UNITS FOR THE MONTH (MAY)……….98  DEPARTURE…….-10
TOTAL HEATING UNITS FOR THE SEASON………….5934  DEPARTURE…….-61
TOTAL HEATING UNITS LAST SEASON TO DATE……..5468  DEPARTURE……+466

COOLING DEGREE DAYS (SEASON: JAN 2026 THRU DEC 2026)
TOTAL COOLING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH (MAY)………..0  DEPARTURE……..-4
TOTAL COOLING UNITS FOR THE SEASON…………….6  DEPARTURE……..-1
TOTAL COOLING UNITS LAST SEASON TO DATE………..7  DEPARTURE……..-1

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)………..28 SSW  @   12:31 P.M.
VECTOR #1 (1-Sec)……….28 SSW  @   12:31 P.M.
VECTOR #2 (1-Sec)……….27 SSW  @   02:43 P.M.
DAVIS #1……………….29 S    @   12:27 P.M.
DAVIS #2 ………………30 S    @   02:43 P.M.
RMY #1 (Instantaneous)…..27 SW   @   11:21 A.M.
RMY #2 (Instantaneous)…..28 SW   @   11:21 A.M.
MERLIN…………………25 SW
RICHARDS (C5C) (Inst)……26 SSW  @   12:31 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………17 SW   @   04:03 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..20 SSW  @   02:45 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..20 SSW  @   02:44 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………20 S    @   02:45 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………20 S    @   02:44 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..19 SSW  @   02:45 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..20 SSW  @   02:44 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………18 SSW  @   02:45 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………8.8 SW [212 total miles] VECTOR #1………………10.1
VECTOR #2………………10.5
DAVIS #1………………..9.8 SW
DAVIS #2……………….10.5 SW
RMY #1………………….9.9 SW
RMY #2…………………10.5 WSW
RICHARDS (C5C)…………..9.7

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….TRACE DEPARTURE…..-0.11
TOTAL PRECIPITATION FOR THE MONTH (MAY)……..0.69 DEPARTURE…..-0.53
TOTAL PRECIPITATION FOR THE YEAR (2026)…….14.36 DEPARTURE…..-5.64

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE……0.0
TOTAL SNOWFALL FOR THE MONTH (MAY)…………..0.0 DEPARTURE……0.0
TOTAL SNOWFALL FOR THE SEASON (2025-2026)……81.6 DEPARTURE….+11.9

————————————————————–

PRELIMINARY CLIMATE SUMMARY FOR MAY 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

5/1  63/43/53/0/0.00/769/91              26 WNW VEC1 27 NNW RMY 27
5/2  58/45/52/-2/0.04/127/15             29 SSW VEC1 29 SSW RMY 28
5/3  53/41/47/-7/T/119/14                37 NW  VEC1 36 NW  RMY 39
5/4  71/41/56/+2/0.00/775/91             46 SW  VEC1 46 SW  RMY 48
5/5  78/49/64/+9/0.00/718/84             43 SSW VEC1 43 SSW RMY 45
5/6  68/54/61/+6/0.08/146/17             43 SSW VEC1 42 SSW RMY 44
5/7  65/46/56/+1/0.22/…/..             28 WNW VEC1 27 WNW RMY 28
5/8  62/40/51/-4/0.00/…/..             33 W   VEC1 33 W   RMY 33
5/9  58/43/51/-5/0.35/…/..             30 SSW VEC1 31 SSW RMY 30
5/10 72/49/61/+5/T/…/..                28 SSW VEC1 28 SSW RMY 27

5/11 The low since midnight is 50F, the daily normal low is 47F.

————————————————————–

MAY DAILY RECORDS TO DATE

NONE.

————————————————————–

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

RECORDS FOR MAY 11
HIGH 90F IN 1993
LOW 28F IN 1900
PRECIP 1.28 INS IN 1957
SNOW 1.0 INS IN 1907 (LATEST MEASURABLE SNOW ON RECORD)
PEAK GUST 75e MPH NW IN 1945

RECORDS FOR MAY 12
HIGH 88F IN 2001
LOW 29F IN 1907
PRECIP 1.49 INCHES IN 1968
SNOW TRACE IN 2019
PEAK GUST 76 MPH S IN 1974

TODAY’S REPORT PREPARED BY: Matt Douglas

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Effective January 1, 2025 · Milton, Massachusetts · bluehill.org
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