Tuesday, April 21, 2026

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

TUESDAY, APRIL 21, 2026
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0454E
SUNSET: 1833E

MAINLY SUNNY TODAY WITH A LIGHT WIND, BUT STILL ON THE CHILLY SIDE….

Skies started off the day on the clear side giving us a very nice
sunrise this morning behind some offshore clouds. As the heating
of the day increased during the morning hours, some low level
stratocumulus clouds have popped up. Higher cirrostratus and cirrus
clouds have also joined the mix early this afternoon helping to filter
the sun a bit.

Temperatures are once again below normal as the cold air mass of
the past day or two continues over the region. We started the day
below freezing once again with a low of 31F. It has “warmed” to
into the upper 40s by early this afternoon. Dew point values
continue on the low side, and have actually been dropping since
early this morning. Values started the day in the mid 20s, but have
dropped into the mid to upper teens by early this afternoon. This
is indicative of the equivalent of an arctic air mass. Thankfully
it’s mid April and not mid January!

Winds have been mainly on the light side today out of mainly a
northerly direction. The average speed for the day so far is only
around 7mph. The peak gust so far today is 18mph, which occurred
just after 10am this morning.

Visibility has been excellent all day with a view of around 70
miles!

The maximum temperature so far today is 48 degrees, which is
11 degrees below the normal high of 59F. The minimum temperature
since midnight is 31F degrees, which is 9 degrees below the
normal low of 40F.

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Today’s Observations:

7 A.M.
Weather: Clear, few stratocumulus distant NE-SE-SSW, few altocumulus
distant E-SSE, few cirrus distant SW-WSW
Temperature: 38F; Dew Point: 23F; Relative Humidity: 53%
Wind: NE @ 4 kts, wind light
Sea-level pressure: 1029.3 mb; 30.40 in. Hg: rising, then more slowly
Visibility: 70 miles
6-hr Max temp: 38F
6-hr Min temp: 31F
24-hr Precip: Trace
24-hr Snowfall: Trace
Snow Depth: 0 inches
BHO SA 1155 CLR 70 293/38/23/0404/040/ FEW SC DSNT NE-SE-SSW
FEW AC DSNT E-SSE FEW CI DSNT SW-WSW WND LGT TOTAL NEW SNW
PST 24 HRS TRACE/ 8/551 51015 70000 10038 20031

10 A.M.
Weather: Scattered stratocumulus, scattered cirrus
Temperature: 44F; Dew Point: 17F; Relative Humidity: 33%
Wind: NNW @ 3 kts, wind light and variable
Sea-level pressure: 1028.5 mb; 30.37 in. Hg: rising, then falling
Visibility: 70 miles
3-hr Precip: 0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 55 SCT 250 SCT 70 285/44/17/3303/037/ WND L/V/ 8/501 58008

1 P.M.
Weather: Scattered stratocumulus, scattered cirrostratus, broken cirrus
Temperature: 48F; Dew Point: 18F; Relative Humidity: 30%
Wind: WSW @ 5 kts, wind light and variable
Sea-level pressure: 1026.6 mb; 30.32 in. Hg: falling, then more slowly
Visibility: 70 miles
6-hr Max temp: 48F
6-hr Min temp: 38F
6-hr Precip: 0.00 inches
6-hr Snowfall: 0.0 inches
Snow Depth: 0 inches
BHO SA 1755 55 SCT 200 SCT E250 BKN 70 266/48/18/2505/032/
WND L/V/ 8/505 56019 10048 20038

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SUMMARY FOR MONDAY, APRIL 20, 2026

TEMPERATURE (DEGREES F)
MAX…….50 NORMAL…..59
MIN…….31 NORMAL…..40
MEAN……41 NORMAL…..49

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-8
TOTAL DEPARTURE FOR THE MONTH………………………+66 [+3.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY…………….24 DEPARTURE……..+8
TOTAL HEATING UNITS FOR THE MONTH (MAR)………339 DEPARTURE…….-62
TOTAL HEATING UNITS FOR THE SEASON………….5657 DEPARTURE…….-91
TOTAL HEATING UNITS LAST SEASON TO DATE……..5330 DEPARTURE……+327

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)………..31 W @ 09:51 A.M.
VECTOR #1 (1-Sec)……….30 W @ 09:51 A.M.
VECTOR #2 (1-Sec)……….29 W @ 09:51 A.M.
DAVIS #1……………….30 W @ 09:47 A.M.
DAVIS #2 ……………….M
RMY #1 (Instantaneous)…..32 W @ 09:51 A.M.
RMY #2 (Instantaneous)…..30 W @ 09:51 A.M.
MERLIN…………………30 NW
RICHARDS (C5C) (Inst)……28 W @ 09:51 A.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………19 W @ 09:52 A.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..20 W @ 09:51 A.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..21 WNW @ 12:05 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………21 WSW @ 09:51 A.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE…………….M
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..20 W @ 09:51 A.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..20 WNW @ 12:04 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………20 NW @ 02:09 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL………9.8 NW [236 total miles] VECTOR #1………………10.4
VECTOR #2………………10.7
DAVIS #1……………….10.7 WNW
DAVIS #2………………….M
RMY #1…………………10.1 WNW
RMY #2…………………10.5 WNW
RICHARDS (C5C)………….10.5

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….TRACE DEPARTURE…..-0.15
TOTAL PRECIPITATION FOR THE MONTH (APR)……..1.79 DEPARTURE…..-1.53
TOTAL PRECIPITATION FOR THE YEAR (2026)…….13.46 DEPARTURE…..-3.88

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………TRACE DEPARTURE…..-0.1
TOTAL SNOWFALL FOR THE MONTH (APR)…………TRACE DEPARTURE…..-2.6
TOTAL SNOWFALL FOR THE SEASON (2025-2026)……81.6 DEPARTURE….+12.1

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PRELIMINARY CLIMATE SUMMARY FOR APRIL 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

4/1 73/38/56/+15/0.16/0.0/061/08 35 NE VEC1 34 ENE RMY 35
4/2 38/34/36/-5/0.45/0.0/000/00 31 E VEC1 31 E RMY 33
4/3 67/35/51/+9/0.04/0.0/270/35 31 SW VEC1 31 SW RMY 35
4/4 58/35/47/+5/0.01/0.0/093/12 39 ENE VEC1 38 ENE RMY 42
4/5 55/36/46/+3/0.16/0.0/008/01 35 NW VEC1 36 NW RMY 38
4/6 50/32/41/-2/0.00/0.0/708/91 46 WNW VEC1 46 WNW RMY 47
4/7 50/29/40/-4/0.10/T/336/43 39 WNW VEC1 39 WNW RMY 41
4/8 43/25/34/-10/0.00/0.0/753/96 30 NNW VEC1 31 NNW RMY 32
4/9 56/30/43/-1/0.00/0.0/755/96 35 S VEC1 35 SSW RMY 35
4/10 67/33/50/+5/0.00/0.0/672/85 37 S VEC1 36 SSW RMY 37
4/11 60/41/51/+6/0.00/0.0/690/87 37 NW VEC1 37 NW RMY 37
4/12 54/35/45/-1/0.02/0.0/549/69 28 S VEC1 28 S RMY 28
4/13 69/41/55/+9/T/0.0/168/21 40 SSW VEC1 41 SSW RMY 42
4/14 83/58/71/+24/0.15/0.0/617/77 46 SSW VEC1 46 SSW RMY 47
4/15 77/44/61/+14/T/0.0/626/78 25 NE VEC1 25 NE RMY 24
4/16 69/45/57/+10/0.37/0.0/…/.. 45 NW VEC1 44 NW RMY 50 TSTM
4/17 62/47/55/+7/0.14/0.0/…/.. 31 NE VEC1 32 NNW RMY 31
4/18 48/41/45/-3/0.04/0.0/…/.. 28 ENE VEC1 26 E RMY 27
4/19 49/34/42/-7/0.14/T/…/.. 40 NW VEC1 39 NW RMY 42 TSTM
4/20 50/31/41/-8/T/T/…/.. 31 W VEC1 30 W RMY 32