Tuesday, May 13, 2025

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

TUESDAY, MAY 13, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0425E
SUNSET:  1857E

COMFORTABLE TEMPERATURES ONCE AGAIN WITH FILTERED SUNSHINE….

Today has featured plenty of sunshine, albeit filtered through
thin cirrus clouds. Somewhat thicker cirrostratus clouds have
been observed to the distant south through west, but for now
they haven’t made much progress toward the area. The high pollen
count is once again the only negative of the day which is reducing
visibility a bit as seen by increased haziness.

Temperatures are slightly above seasonal levels for this time of
year with readings in the upper 60s to 70F. Dew point values
are starting to rise a bit, from the upper 30s this morning to the
mid 40s by early this afternoon. However, it’s still a very
comfortable air mass in place.

Winds have been fairly steady most of the day out of an easterly
direction. The average speed for the day so far is around 10mph.
There have been occasional gusts over 20mph, but they have been
rather infrequent. The peak gust so far is 26mph, which occurred
just before 10am this morning.

Visibility has been decent, although it has decreased a bit as
mentioned above due to the increase in pollen in the air. The view
started the day around 60 miles, but has slipped to around 45-50
miles by early this afternoon.

The maximum temperature for today is 70F degrees, which is 4 degrees
above the normal high of 66F. The minimum temperature since midnight
is 56F degrees, which is 9 degrees above the normal low of 47F.

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Today’s Observations:

7 A.M.
Weather: Thin broken cirrus
Temperature: 61F; Dew Point: 40F; Relative Humidity: 46%
Wind: ESE @ 10G16 kts
Sea-level pressure: 1025.6 mb; 30.29 in. Hg: rising, then more rapidly
Visibility: 60 miles
6-hr Max temp: 61F
6-hr Min temp: 56F
24-hr Precip:  0.00 inches
24-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1155 E250 -BKN 60 256/61/40/1110G16/029/ 8/001 53022 10061 20056

10 A.M.
Weather: Thin broken cirrus, few cirrostratus distant SSW-W
Temperature: 68F; Dew Point: 38F; Relative Humidity: 33%
Wind: SE @ 10G23 kts
Sea-level pressure: 1026.4 mb; 30.31 in. Hg: rising, then more slowly
Visibility: 50 miles
3-hr Precip:  0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 E250 -BKN 50 264/68/38/1310G23/031/ FEW CS DSNT SSW-W/
8/005 51008

1 P.M.
Weather: Thin broken cirrus
Temperature: 67F Dew Point: 46F; Relative Humidity: 48%
Wind: NE @ 8G16 kts
Sea-level pressure: 1025.8 mb; 30.29 in. Hg: falling, then more rapidly
Visibility: 50 miles
6-hr Max temp: 70F
6-hr Min temp: 61F
6-hr Precip:  0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 E250 -BKN 50 258/67/46/0508G16/029/ 8/001 58006 10070 20061

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SUMMARY FOR MONDAY, MAY 12, 2025

TEMPERATURE (DEGREES F)
MAX…….73   NORMAL…..66
MIN…….46   NORMAL…..47
MEAN……60   NORMAL…..57

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+3
TOTAL DEPARTURE FOR THE MONTH………………………+44 [+3.5 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2024 THRU JUN 2025)
TOTAL HEATING UNITS FOR YESTERDAY……………..5  DEPARTURE……..-4
TOTAL HEATING UNITS FOR THE MONTH…………….80  DEPARTURE…….-46
TOTAL HEATING UNITS FOR THE SEASON………….5478  DEPARTURE……-535
TOTAL HEATING UNITS LAST SEASON TO DATE……..5301  DEPARTURE……+177

COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE MONTH……………..4  DEPARTURE……..-1
TOTAL COOLING UNITS FOR THE SEASON…………….7  DEPARTURE……..-1
TOTAL COOLING UNITS LAST SEASON TO DATE………..2  DEPARTURE……..+5

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)………..36 SW   @   03:41 P.M.
VECTOR #1 (1-Sec)……….34 SW   @   02:21 P.M.
VECTOR #2 (1-Sec)……….36 SW   @   02:21 P.M.
DAVIS #1……………….36 S    @   01:13 P.M.
DAVIS #2 ………………33 S    @   09:30 A.M.
RMY #1 (Instantaneous)…..36 SW   @   03:40 P.M.
RMY #2 (Instantaneous)…..37 SW   @   02:21 P.M.
MERLIN…………………33 SW
RICHARDS (C5C) (Inst)…..OTS

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………24 SW   @   03:30 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..23      @   03:30 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..25      @   03:30 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………23 SW   @   03:30 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………25 WSW  @   03:29 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..23 SW   @   03:30 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..25 SW   @   03:30 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..13.0 SW [312 total miles] VECTOR #1………………13.1
VECTOR #2………………13.6
DAVIS #1……………….12.9 SW
DAVIS #2……………….13.7 SW
RMY #1…………………12.8 SW
RMY #2…………………13.6 SW
RICHARDS (C5C)…………..OTS

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.11
TOTAL PRECIPITATION FOR THE MONTH…………..2.72 DEPARTURE…..+1.27
TOTAL PRECIPITATION FOR THE YEAR (2025)…….16.84 DEPARTURE…..-3.39

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

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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/…/..        18 ESE VEC1 18 ESE RMY 18
5/9   51/46/49/-7/1.15/0.0/…/..        33 E   VEC1 34 ENE RMY 35
5/10  62/45/54/-2/0.29/0.0/…/..        36 NW  VEC1 37 NW  RMY 41
5/11  70/49/60/+4/0.00/0.0/…/..        33 NW  VEC1 32 NW  RMY 34
5/12  73/46/60/+3/0.00/0.0/…/..        36 SW  VEC1 34 SW  RMY 36

5/13 The low since midnight is 56F, the daily normal low is 47F.

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MAY 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 MAY 13
HIGH 85F IN 1947
LOW 32F IN 2020
PRECIP 2.39 INCHES IN 2006
PEAK GUST 49 MPH NNW IN 1965

RECORDS FOR MAY 14
HIGH 85F IN 1961,2022
LOW 33F IN 1895
PRECIP 1.93 INCHES IN 2006
PEAK GUST 53 MPH S IN 2009

TODAY’S REPORT PREPARED BY: MFD