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BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
MONDAY, MAY 18, 2026
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0420E
SUNSET: 1902E
VERY WARM CONDITIONS CONTINUE WITH ANOTHER DAY OF SUNSHINE….
High pressure continues to be anchored near Bermuda with another
weaker area of high pressure over northern Maine. Aloft a ridge is
continuing to build into the region bringing a very summerlike
air mass with it. The weak high to the north did help push a weak
backdoor front through the area overnight, allowing for a brief
reprieve from the hot temperatures which began yesterday.
Sunshine continues to the theme today with some mid and high
level clouds around. As mentioned, a backdoor cold front crossed
the area overnight with an onshore flow taking over helping to
keep coastal areas a bit cooler today. Nonetheless, it’s another
perfect day for any and all outdoor activities if one is lucky
enough to have the day off!
Temperatures have reached the low to mid 80s here at Blue Hill
as the onshore flow this morning has become southerly. The dew
point did drop into the mid to upper 40s early this morning as
drier air briefly pushed in from northern New England. As the
wind has taken on a southerly direction, dew point values have
risen back into the low to mid 50s by early this afternoon.
Winds were steady following the passage of the backdoor front
right around midnight. They were gusty for a time for a few hours
following the frontal passage. However winds diminished markedly
by the late morning hours, becoming light and variable for a time
before shifting to the south by early this afternoon. The average
speed for the day so far is around 10mph, but the trend has been
downward since around 7am. The peak gust so far for the day is
25mph, which occurred just after 2am this morning.
Visibility has been limited again today due to haziness, mostly
due to the high pollen count. The view has been stuck at around
40 miles all day.
The maximum temperature so far today is 83F degrees, which is
16 degrees above the normal high of 67F. The minimum temperature
since midnight is 62F degrees, which is 13 degrees above the
normal low of 49F.
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Today’s Observations:
7 A.M.
Weather: Scattered altocumulus/castellanus, broken cirrus
Temperature: 65F; Dew Point: 47F; Relative Humidity: 52%
Wind: SE @ 10G16 kts
Sea-level pressure: 1024.1 mb; 30.24 in. Hg: rising, then more slowly
Visibility: 40 miles, hazy
6-hr Max temp: 69F
6-hr Min temp: 62F
24-hr Precip: 0.00 inches
BHO SA 1155 75 SCT E250 BKN 40 241/65/47/1310G16/024/ HAZY/
8/081 51018 10069 20062
10 A.M.
Weather: Thin broken cirrus, few altocumulus/castellanus all quadrants
Temperature: 77F; Dew Point: 51F; Relative Humidity: 40%
Wind: SSE @ 4 kts, wind light and variable
Sea-level pressure: 1024.2 mb; 30.24 in. Hg: rising, then falling
Visibility: 40 miles, hazy
3-hr Precip: 0.00 inches
BHO SA 1455 E250 -BKN 40 242/77/51/1504/024/ FEW AC/ACC ALQDS
HAZY WND L/V/ 8/081 50001
1 P.M.
Weather: Thin broken cirrus
Temperature: 83F; Dew Point: 54F; Relative Humidity: 37%
Wind: S @ 7G16 kts
Sea-level pressure: 1021.9 mb; 30.18 in. Hg: falling, then more rapidly
Visibility: 40 miles, hazy
6-hr Max temp: 83F
6-hr Min temp: 65F
6-hr Precip: 0.00 inches
BHO SA 1755 E250 -BKN 40 219/83/54/1807G16/018/ HAZY/
8/001 58023 10083 20065
————————————————————–
SUMMARY FOR SUNDAY, MAY 17, 2026
TEMPERATURE (DEGREES F)
MAX…….86 NORMAL…..67
MIN…….56 NORMAL…..49
MEAN……71 NORMAL…..58
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………+13
TOTAL DEPARTURE FOR THE MONTH……………………….+9 [+0.3 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..0 DEPARTURE……..-8
TOTAL HEATING UNITS FOR THE MONTH (MAY)………155 DEPARTURE…….-13
TOTAL HEATING UNITS FOR THE SEASON………….5991 DEPARTURE…….-64
TOTAL HEATING UNITS LAST SEASON TO DATE……..5486 DEPARTURE……+505
COOLING DEGREE DAYS (SEASON: JAN 2026 THRU DEC 2026)
TOTAL COOLING UNITS FOR YESTERDAY……………..6 DEPARTURE……..+5
TOTAL COOLING UNITS FOR THE MONTH (MAY)………..6 DEPARTURE……..-3
TOTAL COOLING UNITS FOR THE SEASON……………12 DEPARTURE………0
TOTAL COOLING UNITS LAST SEASON TO DATE……….14 DEPARTURE……..-2
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)………..39 W @ 12:50 P.M.
VECTOR #1 (1-Sec)……….38 W @ 12:50 P.M.
VECTOR #2 (1-Sec)……….37 W @ 12:48 P.M.
DAVIS #1……………….36 W @ 12:50 P.M.
DAVIS #2 ………………36 W @ 12:48 P.M.
RMY #1 (Instantaneous)…..40 W @ 12:50 P.M.
RMY #2 (Instantaneous)…..38 W @ 12:48 P.M.
MERLIN…………………36 W
RICHARDS (C5C) (Inst)……37 WNW @ 12:54 P.M.
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………25 W @ 12:51 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..24 W @ 12:50 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..26 WNW @ 12:55 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………25 W @ 12:50 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………26 WNW @ 12:55 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..23 W @ 12:50 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..25 WNW @ 12:55 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………23 W @ 12:50 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..12.2 W [292 total miles]
VECTOR #1………………12.2
VECTOR #2………………12.6
DAVIS #1……………….12.5 W
DAVIS #2……………….12.5 W
RMY #1…………………12.0 W
RMY #2…………………12.4 W
RICHARDS (C5C)………….11.9
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.12
TOTAL PRECIPITATION FOR THE MONTH (MAY)……..1.04 DEPARTURE…..-0.99
TOTAL PRECIPITATION FOR THE YEAR (2026)…….14.71 DEPARTURE…..-6.10
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/+1/0.22/697/81 28 WNW VEC1 27 WNW RMY 28
5/8 62/40/51/-4/0.00/741/86 33 W VEC1 33 W RMY 33
5/9 58/43/51/-5/0.35/000/00 30 SSW VEC1 31 SSW RMY 30
5/10 72/49/61/+5/T/346/40 28 SSW VEC1 28 SSW RMY 27
5/11 62/45/54/-2/T/191/22 26 NNW VEC1 26 NNW RMY 26
5/12 63/42/53/-4/T/835/96 29 WNW VEC1 29 WNW RMY 29
5/13 65/46/56/-1/T/122/14 41 S VEC1 40 S RMY 44
5/14 61/48/55/-2/0.26/…/.. 37 SSE VEC1 38 SE RMY 36
5/15 56/47/52/-5/0.04/…/.. 18 NE VEC1 19 NE RMY 20
5/16 78/47/63/+5/0.00/…/.. 33 SW VEC1 34 SSW RMY 35
5/17 86/56/71/+13/0.05/…/.. 39 W VEC1 38 W RMY 40
5/18 The low since midnight is 62F, the daily normal low is 49F.
————————————————————–
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 18
HIGH 96F IN 2017(RECORD FOR MAY)
LOW 35F IN 2002
PRECIP 1.93 INS IN 2007
SNOW TRACE IN 2002 (Ice pellets)
PEAK GUST 64 MPH SSW IN 2000
RECORDS FOR MAY 19
HIGH 91F IN 1962
LOW 34F IN 2002
PRECIP 1.54 INCHES IN 1900
PEAK GUST 58 MPH NW IN 1964
TODAY’S REPORT PREPARED BY: Matt Douglas
