Saturday, May 17, 2025
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
SATURDAY, MAY 17, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0421E
SUNSET: 1901E
OVERCAST AND HUMID ON THIS SATURDAY….
Much like yesterday, we started the day with dense fog here on the
summit which burned off rather quickly leaving us with just cloudy
skies for the balance of the day to this point. A touch of drizzle
also occurred occasionally during the mid morning hours, but was
very light and didn’t amount to more than a trace.
Temperatures have been held back a bit to this point with readings
reaching the upper 60s to near 70F so far. Dew points are still
running in the low to mid 60s, so it’s still feeling on the humid
side again today.
Winds have been fairly steady out of the south and south-southwest.
The average speed for the day so far is around 12mph. The peak gust
so far for today is 26mph, which occurred just before 9:30am this
morning.
Visibility has been gradually improving, but still limited. The
view as nearly nonexistent early this morning with the visibility
down to 1/16th of a mile. It has only improved to around 20-25 miles
as thin fog and haziness have been hanging around for the balance of
the day so far.
The maximum temperature for today is 69F degrees, which is 2 degrees
above the normal high of 67F. The minimum temperature since midnight
is 58F degrees, which is 9 degrees above the normal low of 49F.
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Today’s Observations:
7 A.M.
Weather: Sky obscured, vertical visibility 100ft, very light drizzle
Temperature: 60F; Dew Point: 60F; Relative Humidity: 100%
Wind: SSW @ 10G15 kts
Sea-level pressure: 1005.7 mb; 29.70 in. Hg: rising, then falling
Visibility: 1/16th mile, fog
6-hr Max temp: 62F
6-hr Min temp: 58F
24-hr Precip: Trace
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 X W1 1/16L-F 057/60/60/2010G15/970/ L-B08 PCPN VRY LGT/
8//// 58002 6000/ 70000 10062 20058
10 A.M.
Weather: Overcast stratus
Temperature: 66F; Dew Point: 63F; Relative Humidity: 90%
Wind: SSW @ 12G21 kts
Sea-level pressure: 1003.8 mb; 29.64 in. Hg: falling, then more rapidly
Visibility: 15 miles, 10 miles S-W-NW 20 miles NE-ENE, thin fog
3-hr Precip: Trace
3-hr Snowfall: 0.0 inches
BHO SA 1455 E12 OVC 15 038/66/63/1912G21/964/ THN F ALQDS L-B20E38
VSBY 10 S-W-NW 20 NE-ENE/ 8/6// 58019 6000/
1 P.M.
Weather: overcast altocumulus/altostratus, few stratus fractus all
quadrants
Temperature: 69F Dew Point: 63F; Relative Humidity: 81%
Wind: SW @ 8G15 kts
Sea-level pressure: 1002.4 mb; 29.60 in. Hg: falling, then more rapidly
Visibility: 25 miles, hazy
6-hr Max temp: 69F
6-hr Min temp: 60F
6-hr Precip: Trace
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 E120 OVC 25 024/69/63/2208G15/960/ FEW STFRA AQLDS HAZY/
8/57/ 58014 6000/ 10069 20060
————————————————————–
SUMMARY FOR FRIDAY, MAY 16, 2025
TEMPERATURE (DEGREES F)
MAX…….78 NORMAL…..67
MIN…….61R NORMAL…..48
MEAN……70 NORMAL…..58
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL……………+12
TOTAL DEPARTURE FOR THE MONTH………………………+72 [+4.3 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………..0 DEPARTURE……..-8
TOTAL HEATING UNITS FOR THE MONTH…………….88 DEPARTURE…….-72
TOTAL HEATING UNITS FOR THE SEASON………….5486 DEPARTURE……-561
TOTAL HEATING UNITS LAST SEASON TO DATE……..5325 DEPARTURE……+161
COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..5 DEPARTURE……..+4
TOTAL COOLING UNITS FOR THE MONTH……………..9 DEPARTURE……..+1
TOTAL COOLING UNITS FOR THE SEASON……………12 DEPARTURE……..+1
TOTAL COOLING UNITS LAST SEASON TO DATE………..2 DEPARTURE…….+10
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)………..23 SW @ 09:57 P.M.
VECTOR #1 (1-Sec)……….23 SSW @ 02:59 P.M.
VECTOR #2 (1-Sec)……….24 SSW @ 09:57 P.M.
DAVIS #1……………….23 S @ 02:59 P.M.
DAVIS #2 ………………25 S @ 02:40 P.M.
RMY #1 (Instantaneous)…..23 SW @ 09:57 P.M.
RMY #2 (Instantaneous)…..25 SSW @ 09:57 P.M.
MERLIN………………….M
RICHARDS (C5C) (Inst)…..OTS
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………17 SSW @ 08:40 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..18 @ 09:57 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..19 @ 09:57 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………17 S @ 08:32 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………18 SSW @ 09:57 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..17 SW @ 09:57 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..19 SSW @ 09:57 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………7.7 SSW [184 total miles]
VECTOR #1……………….8.3
VECTOR #2……………….8.5
DAVIS #1………………..7.7 SSW
DAVIS #2………………..8.4 SSW
RMY #1………………….8.1 SW
RMY #2………………….8.6 SSW
RICHARDS (C5C)…………..OTS
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….TRACE DEPARTURE…..-0.11
TOTAL PRECIPITATION FOR THE MONTH…………..3.34 DEPARTURE…..+1.43
TOTAL PRECIPITATION FOR THE YEAR (2025)…….17.46 DEPARTURE…..-3.23
SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………..0.0 DEPARTURE…….0.0
TOTAL SNOWFALL FOR THE MONTH………………..0.0 DEPARTURE…….0.0
TOTAL SNOWFALL FOR THE SEASON (2024-2025)……35.8 DEPARTURE…..-33.9
————————————————————–
PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/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 69/43/56/+3/0.00/0.0/744/88 28 S VEC1 28 SSW RMY 28
5/2 79/47/63/+9/0.19/0.0/339/40 28 SE VEC1 29 SE RMY 25 TSTM
5/3 84/54/69/+15/0.15/0.0/561/66 43 SSW VEC1 42 SSW RMY 44 TSTM
5/4 77/50/64/+10/0.06/0.0/256/30 33 SW VEC1 34 SW RMY 32
5/5 50/46/48/-7/0.26/0.0/000/00 35 ENE VEC1 35 ENE RMY 36
5/6 61/48/55/0/0.57/0.0/000/00 26 S VEC1 27 ENE RMY 27
5/7 72/54/63/+8/0.01/0.0/310/36 33 SSW VEC1 33 SW RMY 35
5/8 74/51/63/+8/0.04/0.0/474/55 18 ESE VEC1 18 ESE RMY 18
5/9 51/46/49/-7/1.15/0.0/000/00 33 E VEC1 34 ENE RMY 35
5/10 62/45/54/-2/0.29/0.0/121/14 36 NW VEC1 37 NW RMY 41
5/11 70/49/60/+4/0.00/0.0/851/98 33 NW VEC1 32 NW RMY 34
5/12 73/46/60/+3/0.00/0.0/853/98 36 SW VEC1 34 SW RMY 36
5/13 70/51/61/+4/0.00/0.0/759/87 26 ESE VEC1 27 ESE RMY 26
5/14 73/48/61/+4/0.00/0.0/586/67 18 SSE VEC1 19 SSE RMY 17
5/15 72/58/65/+8/0.62/0.0/079/09 20 SSE VEC1 20 SSE RMY 19 TSTM
5/16 78/61/70/+12/0.00/0.0/404/46 23 SW VEC1 23 SSW RMY 23
5/17 The low since midnight is 58F, the daily normal low is 49F.
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MAY DAILY RECORDS TO DATE
5/16 RECORD HIGH MINIMUM TEMPERATURE OF 61F;
PREVIOUS RECORD WAS 60F SET IN 2014
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DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR MAY 17
HIGH 90F IN 2017
LOW 34F IN 1956, 1957
PRECIP 2.07 INS IN 1916
PEAK GUST 52 MPH SW IN 1967, W IN 1974
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
TODAY’S REPORT PREPARED BY: MFD
