Dalecarlia Reservoir, Maryland climate: Climate normals at a NOAA weather station

What is the weather like at Dalecarlia Reservoir each month?

July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 26°F. The most precipitation falls in July (5.11 in), the least in February (3.24 in).

Which months are mildest at Dalecarlia Reservoir?

Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, October has the fewest days with rain (9).

That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.

When is the last frost at Dalecarlia Reservoir?

In Dalecarlia Reservoir, the last spring frost (32°F) comes after April 9 in half of years and after April 26 in one year in ten; the first autumn frost comes before October 31 in half of years and before October 16 in one year in ten.

Last spring frost, half of years after

April 91 year in 10 after April 26; 9 in 10 after March 27

First autumn frost, half of years before

October 311 year in 10 before October 16; 9 in 10 before November 13

NOAA puts the median frost-free season at 202 days, and the season without a hard freeze (28°F) at 226 days.

A hard freeze (28°F) comes after March 30 in half of springs and before November 9 in half of autumns.

The USDA's 2023 Plant Hardiness Zone Map puts Dalecarlia Reservoir in zone 7b in ZIP code 20816, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 7b: the coldest night of a typical year reaches 8°F (25 complete years).

Frost dates for every NOAA station in Maryland · Frost dates by ZIP code

How hot and how cold does it get at Dalecarlia Reservoir?

In a normal year in Dalecarlia Reservoir, 44 days a year reach 90°F (2 of them 100°F or more), 96 nights fall to 32°F or colder and 123 days bring measurable precipitation.

Days at 90°F or more

44a normal year

Days at 100°F or more

2a normal year

Nights at 32°F or colder

96a normal year

Days that stay below freezing

8high of 32°F or less

Days with 0.01 inch of precipitation

123a normal year

Days with 1 inch of snow or more

3a normal year

The highest temperature in this station's record (since 1948) is 104°F, on August 9, 2007; the lowest is −8°F, on January 19, 1994.

The wettest calendar year on that record is 1972, with 61.07 in; the snowiest season is 2013–14, with 36.1 inches.

How sunny is it at Dalecarlia Reservoir?

Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds at Dalecarlia Reservoir, 4.1 kWh per square metre a day. July is the sunniest month (80%) and January the cloudiest (70%).

How many heating and cooling degree days does Dalecarlia Reservoir record?

A normal year at Dalecarlia Reservoir brings 4,506 heating degree days, 16% fewer than the median U.S. place (5,373), and 1,338 cooling degree days, 47% more than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,035 growing degree days a year above 50°F.

Have recent years at Dalecarlia Reservoir been warmer than normal?

Over 46 complete years from 1951 to 2016, the station's annual mean temperature rose at a fitted 5.6°F per century (+0.31°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.

Which places near Dalecarlia Reservoir share this climate record?

23 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.

• Reston, VAalso near: Vienna (5 mi, 54.0°F a year); Sterling (6 mi, 55.7°F a year)63,542 people · 13 mi W
• McLean, VAalso near: Vienna (6 mi, 54.0°F a year); Washington (11 mi, 59.3°F a year)50,232 people · 4 mi W
• Annandale, VA41,982 people · 9 mi SW
• West Falls Church, VA30,660 people · 6 mi SW
• Tysons, VA28,022 people · 6 mi W
• Fairfax, VA26,340 people · 12 mi SW
• Merrifield, VA20,549 people · 8 mi SW
• Idylwood, VA17,469 people · 6 mi SW
• Burke Centre, VA17,447 people · 14 mi SW
• Wolf Trap, VA16,020 people · 9 mi W
• Falls Church, VA15,034 people · 5 mi SW
• Kings Park West, VA13,281 people · 13 mi SW
• Fairfax Station, VA12,298 people · 16 mi SW
• Wakefield, VA12,024 people · 11 mi SW
• Lake Barcroft, VA10,678 people · 6 mi S
• Woodburn, VA10,046 people · 9 mi SW
• George Mason, VA9,954 people · 13 mi SW
• Seven Corners, VA9,171 people · 5 mi S
• Dunn Loring, VA8,782 people · 7 mi SW
• Mantua, VA7,447 people · 10 mi SW
• Long Branch, VA7,066 people · 11 mi SW
• Pimmit Hills, VA6,395 people · 5 mi SW
• Great Falls Crossing, VA1,384 people · 12 mi W

Nearby and next

• Maryland climateThe statewide normals and every place in the state
• Washington, DC7 miles from this station, 59.3°F a year
• National Arboretum DC, MD8 miles from this station, 58.3°F a year
• Vienna, VA10 miles from this station, 54.0°F a year
• Rockville, MD11 miles from this station, 56.2°F a year
• Compare two placesMonth by month, side by side

Download these normals (CSV) · JSON · How these figures are made