Monday, April 20, 2026

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

MONDAY, APRIL 20, 2026
ALL TIMES ARE IN EASTERN STANDARD TIME (EST)
SUNRISE: 0455E
SUNSET: 1832E

CLEAR START TO THE DAY, THEN CLOUDS RAPIDLY INCREASE BY LATE MORNING….

Skies started off the day on the clear, but cold side. Once the sun
started to heat the ground, clouds quickly popped up thanks to a
very cold pool of air aloft. Showers of both rain and snow have also
developed thanks to the moderate convection taking place today.

Temperatures are once again below normal as a very cold air mass
for this time of year is over the region. We started the day below
freezing with a low of 31F. It “warmed” to the upper 40s to 50F
early this afternoon. Dew point values have been generally in the
low 30s today, helping to add a further chill to the air.

Winds have been fairly steady today out of a westerly direction.
The average speed for the day so far is around 11mph. The peak gust
for the day so far is 31mph, which occurred just before 10am this
morning.

Visibility has been decent today with the view varying between
50-70 miles today, dropping lower at times due to rain and snow
showers in the area.

The maximum temperature so far today is 50F degrees, which is
9 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 WNW-N, few altocumulus
distant SW-W, few cirrus distant NE-SE
Temperature: 36F; Dew Point: 29F; Relative Humidity: 74%
Wind: W @ 9 kts
Sea-level pressure: 1020.6 mb; 30.14 in. Hg: rising, then more rapidly
Visibility: 50 miles
6-hr Max temp: 36F
6-hr Min temp: 31F
24-hr Precip: 0.14 inches
24-hr Snowfall: Trace
Snow Depth: 0 inches
BHO SA 1155 CLR 50 206/36/29/2809/014/ FEW SC DSNT WNW-N
FEW AC DSNT SW-W FEW CI DSNT NE-SE TOTAL NEW SNW PST 24 HRS TRACE/
8/551 53023 70014 10036 20031

10 A.M.
Weather: Broken cumulus, broken altocumulus/lenticularis,
broken cirrus, virga distant SW-W
Temperature: 46F; Dew Point: 30F; Relative Humidity: 53%
Wind: W @ 12G27 kts, peak wind W 31mph at 9:51 A.M.
Sea-level pressure: 1021.1 mb; 30.15 in. Hg: rising, then more slowly
Visibility: 70 miles
3-hr Precip: 0.00 inches
3-hr Snowfall: 0.0 inches
BHO SA 1455 E25 BKN 120 BKN 250 BKN 70 211/46/30/2612G27/015/
VIRGA DSNT SW-W PK WND 2727/51/ 8/241/ 51005

1 P.M.
Weather: Broken cumulus, broken altocumulus, virga all quadrants
Temperature: 50F; Dew Point: 32F; Relative Humidity: 49%
Wind: W @ 8G15 kts
Sea-level pressure: 1020.8 mb; 30.14 in. Hg: falling, then steady
Visibility: 70 miles
6-hr Max temp: 50F
6-hr Min temp: 36F
6-hr Precip: Trace
6-hr Snowfall: Trace
Snow Depth: 0 inches
BHO SA 1755 E50 BKN 70 BKN 70 208/50/32/2808G15/014/
VIRGA ALQDS RW-E17B40E46 SW-B40E46 WND 25V31 TOTAL NEW SNW
PST 6 HRS TRACE/ 8/260 56003 6000/ 10050 20036

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SUMMARY FOR SUNDAY, APRIL 19, 2026

TEMPERATURE (DEGREES F)
MAX…….49 NORMAL…..58
MIN…….34 NORMAL…..39
MEAN……42 NORMAL…..49

DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-7
TOTAL DEPARTURE FOR THE MONTH………………………+74 [+3.7 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026)
TOTAL HEATING UNITS FOR YESTERDAY…………….23 DEPARTURE……..+7
TOTAL HEATING UNITS FOR THE MONTH (MAR)………315 DEPARTURE…….-70
TOTAL HEATING UNITS FOR THE SEASON………….5633 DEPARTURE…….-99
TOTAL HEATING UNITS LAST SEASON TO DATE……..5321 DEPARTURE……+312

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)………..40 NW @ 03:35 P.M.
VECTOR #1 (1-Sec)……….39 NW @ 12:51 P.M.
VECTOR #2 (1-Sec)……….41 NW @ 12:52 P.M.
DAVIS #1……………….37 W @ 03:35 P.M.
DAVIS #2 ………………37 NNW @ 12:54 P.M.
RMY #1 (Instantaneous)…..42 NW @ 12:59 P.M.
RMY #2 (Instantaneous)…..44 NW @ 12:54 P.M.
MERLIN…………………39 NW
RICHARDS (C5C) (Inst)……39 NW @ 12:59 P.M.

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………26 NW @ 01:00 P.M.
MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..26 NW @ 12:55 P.M.
MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..29 NW @ 12:54 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………26 NW @ 12:55 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………28 NNW @ 12:54 P.M.
MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..26 NW @ 12:55 P.M.
MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..28 NW @ 12:54 P.M.
MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………26 NW @ 12:55 P.M.

AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……..10.0 NW [241 total miles] VECTOR #1………………10.2
VECTOR #2………………10.8
DAVIS #1……………….10.2 WNW
DAVIS #2……………….10.3 WNW
RMY #1…………………10.1 W
RMY #2…………………10.6 WSW
RICHARDS (C5C)………….10.4

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.14 DEPARTURE……0.00
TOTAL PRECIPITATION FOR THE MONTH (APR)……..1.79 DEPARTURE…..-1.38
TOTAL PRECIPITATION FOR THE YEAR (2026)…….13.46 DEPARTURE…..-3.73

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…………TRACE DEPARTURE……0.0
TOTAL SNOWFALL FOR THE MONTH (APR)…………TRACE DEPARTURE…..-2.5
TOTAL SNOWFALL FOR THE SEASON (2025-2026)……81.6 DEPARTURE….+12.2

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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
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