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BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
MONDAY, JULY 21, 2025
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0426E
SUNSET: 1915E
CANADIAN WILDFIRE SMOKE RETURNS ON A NORTHWEST FLOW, COOLER
AIR WITH LOWER HUMIDITY LEVELS ARRIVE AS WELL….
A line of thunderstorms moved through last evening bringing a
short burst of heavy rainfall to the area. 0.41″ of rain fell
generally within a 50 minute period between 6-7pm. This was
associated with a fairly strong cold front that’s has brought
much more refreshing air (minus the smoke) to the region on a
northwest flow.
Sunshine has mainly been the theme today with an area of mid
level clouds pushing through during the mid morning period.
Diurnal cumulus have also popped up as colder air moves in
aloft as cold air advection is ongoing.
Temperatures have reached the upper 70s early this afternoon
which is actually a bit below normal for this time of year.
The dew point, which has been gradually falling, started the
day in the mid 60s, but have reached the mid 50s by early this
afternoon. They are destined to reach the upper 40s and lower
50s by this evening and overnight. Definitely much more
refreshing than the mid 70s readings 24 hours ago!
The wind has been fairly busy out of the north-northwest to
northwest today. The average speed is around 11mph so far
for the day. Gusts early this afternoon have been reaching
upto around 30mph, with a peak so far of 31mph occurring just
after noon-time.
Visibility has been increasing a bit as the day progresses,
from around 25-30 miles this morning, to around 50 miles by
early this afternoon. The reduction in the view is due purely
to the wildfire smoke which is near surface level as opposed
to aloft.
The maximum temperature so far today is 78F degrees, which is
4 degrees below the normal high of 82F. The minimum temperature
since midnight is 61F degrees, which is 3 degrees below the
normal low of 64F.
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Today’s Observations:
7 A.M.
Weather: Clear, smoke layer all quadrants
Temperature: 67F; Dew Point: 64F; Relative Humidity: 90%
Wind: NNW @ 9 kts
Sea-level pressure: 1010.7 mb; 29.85 in. Hg: rising, then more rapidly
Visibility: 30 miles, hazy
6-hr Max temp: 67F
6-hr Min temp: 61F
24-hr Precip: 0.41 inches
BHO SA 1155 CLR 30 107/67/64/3309/985/ K LYR ALQDS HAZY/ 8/000
53017 10067 20061
10 A.M.
Weather: Scattered cumulus, broken altocumulus castellanus,
smoke layer all quadrants
Temperature: 74F; Dew Point: 59F; Relative Humidity: 56%
Wind: NNW @ 12G20 kts
Sea-level pressure: 1012.4 mb; 29.90 in. Hg: rising, then more slowly
Visibility: 25 miles, hazy
3-hr Precip: 0.00 inches
BHO SA 1455 25 SCT E75 BKN 25 124/74/59/3312G20/990/ K LYR ALQDS
HAZY/ 8/280 51017
1 P.M.
Weather: Broken cumulus, smoke layer all quadrants
Temperature: 74F Dew Point: 57F; Relative Humidity: 54%
Wind: NNW @ 10G18 kts, peak wind NW 31mph at 12:02 P.M.
Sea-level pressure: 1012.9 mb; 29.91 in. Hg: rising, then more rapidly
Visibility: 50 miles, hazy
6-hr Max temp: 78F
6-hr Min temp: 67F
6-hr Precip: 0.00 inches
BHO SA 1755 E50 BKN 50 129/74/57/3310G18/991/ K LYR ALQDS HAZY
PK WND 3127/02/ 8/200 53005 10078 20067
————————————————————–
SUMMARY FOR SUNDAY, JULY 20, 2025
TEMPERATURE (DEGREES F)
MAX…….85 NORMAL…..82
MIN…….65 NORMAL…..64
MEAN……75 NORMAL…..73
DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….+2
TOTAL DEPARTURE FOR THE MONTH………………………+56 [+2.6 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY……………..0 DEPARTURE………0
TOTAL HEATING UNITS FOR THE MONTH……………..1 DEPARTURE……..-4
TOTAL HEATING UNITS FOR THE SEASON…………….1 DEPARTURE……..-4
TOTAL HEATING UNITS LAST SEASON TO DATE………..0 DEPARTURE……..+1
COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025)
TOTAL COOLING UNITS FOR YESTERDAY…………….10 DEPARTURE……..+1
TOTAL COOLING UNITS FOR THE MONTH……………207 DEPARTURE…….+51
TOTAL COOLING UNITS FOR THE SEASON…………..407 DEPARTURE……+112
TOTAL COOLING UNITS LAST SEASON TO DATE………413 DEPARTURE……..-6
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)……….E31 NW @ 06:37 P.M.
VECTOR #1 (1-Sec)……….31 NW @ 06:37 P.M.
VECTOR #2 (1-Sec)……….34 NW @ 06:37 P.M.
DAVIS #1……………….30 WNW @ 06:37 P.M.
DAVIS #2 ………………30 NW @ 06:37 P.M.
RMY #1 (Instantaneous)…..31 NW @ 06:37 P.M.
RMY #2 (Instantaneous)…..34 NW @ 06:37 P.M.
MERLIN…………………28 NW
RICHARDS (C5C) (Inst)…..OTS
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………20 NW @ 06:39 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..20 @ 06:40 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..20 @ 06:38 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………20 NNW @ 06:41 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………19 NNW @ 06:39 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..20 NW @ 06:41 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..19 NW @ 06:38 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE……..OTS
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..10.0 SSW [239 total miles]
VECTOR #1………………10.2
VECTOR #2………………10.8
DAVIS #1………………..9.9 SSW
DAVIS #2……………….10.7 SSW
RMY #1…………………10.0 SW
RMY #2…………………10.9 SSW
RICHARDS (C5C)…………..OTS
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.41 DEPARTURE…..+0.30
TOTAL PRECIPITATION FOR THE MONTH…………..5.61 DEPARTURE…..+3.39
TOTAL PRECIPITATION FOR THE YEAR (2025)…….28.84 DEPARTURE…..-0.61
————————————————————–
PRELIMINARY CLIMATE SUMMARY FOR JULY 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
7/1 90/68/79/+8/0.14/411/45 38 W VEC1 38 W RMY 41 TSTM
7/2 85/69/77/+6/0.02/247/27 23 WSW VEC1 24 WSW RMY 24
7/3 88/63/76/+4/0.03/748/82 39 SW VEC1 39 SW RMY 40 TSTM
7/4 80/60/70/-2/0.00/875/96 28 NNW VEC1 27 NNW RMY 29
7/5 83/61/72/0/0.00/664/73 23 W VEC1 23 W RMY 24
7/6 92/65/79/+7/0.00/818/90 29 SW VEC1 29 SW RMY 29
7/7 88/69/79/+7/0.01/490/54 28 SSW VEC1 28 SSW RMY 29 TSTM
7/8 94/67/81/+9/0.36/562/62 24 WSW VEC1 24 WSW RMY 27 TSTM
7/9 74/65/70/-3/0.73/172/19 26 SW VEC1 27 SW RMY 28 TSTM
7/10 66/61/64/-9/3.85/000/00 24 ENE VEC1 24 ENE RMY 24 TSTM
7/11 80/62/71/-2/0.00/190/21 18 SSW VEC1 18 SSW RMY 18
7/12 84/65/75/+2/0.00/505/56 20 S VEC1 20 S RMY 19
7/13 85/63/74/+1/0.00/505/56 21 SSW VEC1 21 SSW RMY 21
7/14 81/65/73/0/T/216/24 23 SW VEC1 23 SW RMY 25
7/15 90/71/81/+8/0.06/665/74 24 SSW VEC1 24 SSW RMY 24
7/16 93/71/82/+9/0.00/690/77 24 SSW VEC1 24 SSW RMY 23
7/17 89/73/81/+8/0.00/…/.. 41 WNW VEC1 41 WNW RMY 42
7/18 81/67/74/+1/0.00/…/.. 36 WNW VEC1 36 WNW RMY 37
7/19 84/62/73/0/0.00/…/.. 23 SW VEC1 22 SW RMY 21
7/20 85/65/75/+2/0.41/…/.. 31 NW VEC1 31 NW RMY 31 TSTM
7/21 The low since midnight is 65F, the daily normal low is 64F.
————————————————————–
JULY DAILY RECORDS TO DATE
7/10 RECORD HIGHEST PRECIPITATION OF 3.85 INCHES;
BEATING OLD RECORD OF 1.95 INCHES SET IN 2015
7/16 TIED RECORD HIGH MINIMUM TEMPERATURE OF 71F;
ALSO SET IN 1901, 1958, 1968, 2013, AND 2023
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DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR JULY 21
HIGH 100F IN 1977 [RECORD FOR MONTH]
LOW 48F IN 1890
PRECIP 2.09 INS IN 1938
PEAK GUST 60e MPH WNW IN 1977
RECORDS FOR JULY 22
HIGH 99F IN 1926, 2011
LOW 52F IN 1890
PRECIP 1.73 INS IN 1887
PEAK GUST 55 MPH IN 1983
TODAY’S REPORT PREPARED BY: MFD/JN
