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Shaded-relief map of Mason Neck, Virginia: rivers, roads, the city limits and where the water drains.
VIRGINIA · FAIRFAX COUNTY

Mason Neck

2,025 people, 40 ft above sea level in Fairfax County.

40 ftElevation, city center
2,025People, 2024 estimate
14 sq miLand area
Clear 47°
Clear now Dew point 30° · WNW 14 mph · high 46°
City of Mason Neck River Interstate 2 miles
Explore the plate Order a print

The Mason Neck plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.

MILE1
TODAY

Today in Mason Neck

NWS forecast and National Blend of Models · updated 6:00 PM EST
RIGHT NOW DC (KIAD) · 5:52 PM
Clear
47° Clear Feels like 41° · high of 46° near 6 PM
WindWNW 14 mphgusts 23
Humidity52%rising to 82% by morning
Pressure30.01 in →steady
Visibility10 mihaze-free
CloudsClear
UV index—no forecast
Dew point 30° · Dryabout the same for three days
DryComfortableStickyMuggyOppressive
NEXT RAIN
Clear
Not this weeknone in the forecast for a week
LIKELY AMOUNT—nothing expected
LAST RAINNov. 120.02 in · 2 dry days
ALERTS & OUTLOOKS
No watches or warnings for Fairfax County
NWS Baltimore MD/Washington and the Storm Prediction Center · checked 6:47 PM
SUN & MOON
↑ 6:49 AM4:56 PM ↓
10 h 7 m of daylight, 2 minutes less than yesterday
Waxing crescent, 26% lit. Next full moon: Nov. 24.
AIR & POLLEN
25
GOODAir quality index · ozone
Tomorrow: 22, good. No pollen source yet.

The next three days, hour by hour

Sky: clear, cloudy, night Rain likely National Blend of Models
SATURDAY, NOV. 14
SUNDAY, NOV. 15
MONDAY, NOV. 16
TUESDAY, NOV. 17
6p
9p
Mid
3a
6a
9a
Noon
3p
6p
9p
Mid
3a
6a
9a
Noon
3p
6p
9p
Mid
3a
6a
9a
Noon
3p
mostly cloudy night
mostly clear night
mostly clear night
mostly clear night
partly cloudy day
mostly cloudy day
mostly cloudy day
partly cloudy day
partly cloudy night
partly cloudy night
mostly clear night
mostly clear night
mostly sunny
mostly sunny
mostly sunny
mostly sunny
clear night
clear night
clear night
mostly clear night
mostly sunny
clear day
clear day
clear day
TEMPERATURE °F
46°
39°
54°
35°
56°
33°
CHANCE OF RAIN
50%
WIND, MPH
12
12
10
12
9
13
13
13
8
8
7
7
7
10
9
8
6
7
5
5
3
5
6
0
HOW IT FEELS · DEW POINT
Dry: dew points 29 to 36°

The next seven days, and how sure we are

Forecast, with the range 8 in 10 ensemble members agree on Normal, about 57° / 36°
SAT Nov. 14 Partly cloudy Partly cloudy
46° 36°
0% rain — WNW 12 A
SUN Nov. 15 Mostly cloudy; warmer Mostly cloudy; warmer
54° 33°
0% rain — NW 12 A
MON Nov. 16 Mostly sunny Mostly sunny
57° 31°
0% rain — NNW 9 B
TUE Nov. 17 Sunny Sunny
60° 31°
0% rain — WNW 5 A
WED Nov. 18 Sunny Sunny
63° 32°
0% rain — S 5 B
THU Nov. 19 Mostly sunny Mostly sunny
65° 36°
0% rain — S 2 B
FRI Nov. 20 Mostly sunny Mostly sunny
67° 38°
0% rain — NW 5 B
How sure are we? AModels agree: highs within 4° BSome spread: within 8° CWide spread: check back
Range from the National Blend of Models percentiles · graded on Forecast Scores
AIR MAIL

Where today’s air came from

The air arriving over Mason Neck about 5,000 feet above the ground was over British Columbia three days ago, and over the Great Lakes a day ago, about 2,900 miles back along its path. It came down from about 10,000 feet up, warming and drying as it sank. Near the ground the air came from the Canadian Prairies; at 10,000 feet, from the open Pacific. It feels dry all the same. Traced back 72 hours through NOAA’s hourly RAP analyses and the GFS beyond them, nine paths at each of three heights.

THIS WEEK IN 1993 Nov. 15, 1993

The hottest this week has been

83° on Nov. 15, 1993, the hottest reading for this week of the year since 1871. Next is 80° in 1879.

80°
83°
18791993
Source: NOAA RCC-ACIS, the Washington Area threaded record since 1871.
MILE2
THE GROUND

What Mason Neck stands on

Mason Neck’s center stands about 40 ft above sea level. Within three miles the land runs from 0 ft to 160 ft, a difference of 160 ft: gently rolling country. Open water lies within three miles. The highest named summit within 15 miles is Munson Hill, about 370 ft, 15 miles north.

Under the town center the state geologic map shows Shirley Formation (fine-detrital, coarse-detrital), from the Quaternary, less than 2.6 million years old.

The section below crosses 9 rock units mapped at the surface.

Fairfax Station to Port Tobacco Village, cut in half

A section northwest to southeast, 24 miles through the town center
0 ft100 ft200 ft300 ft400 ft MASON NECK40 ftHigh point of the line420 ftLorton110 ftPotomac Riversea levelBryans Road180 ft ← NW · Fairfax StationPort Tobacco Village · SE →

Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 45×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.

Rock at the surface along the line

Occoquan Granite

Granite. Age: Cambrian to Ordovician, 445 to 542 million years old. About 6 mi of the line.

Upland Deposits (Western Shore)

Gravel, sand. Age: Pleistocene, less than 2.6 million years old. About 4 mi of the line.

Pamunkey Group; Nanjemoy Formation

Sand. Age: Eocene, 34 to 56 million years old. About 3 mi of the line.

Potomac Formation

Sand. Age: Cretaceous, 66 to 145 million years old. About 3 mi of the line.

Lowland Deposits

Fine-detrital, coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 2 mi of the line.

Shirley Formation

Fine-detrital, coarse-detrital. Age: Quaternary, less than 2.6 million years old. About 2 mi of the line.

From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 3 smaller units along the line are not listed.

Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.

MILE3
THE WATER

Where Mason Neck’s rain goes

A raindrop that lands in Mason Neck reaches Chesapeake Bay and the Atlantic Ocean by way of Kanes Creek and the Potomac: about 95 river miles.

THE WAY DOWN, TO SCALE
Mason Neck≈ 95 mi · Chesapeake Bay and the Atlantic Ocean
FROM THE CENTER OF MASON NECK ≈ 95 mi to Chesapeake Bay and the Atlantic Ocean Kanes Creek → Potomac

Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mason Neck; river miles along the main stem, rounded.

MILE5
THE ALMANAC

Mason Neck’s year

1991–2020 normals · records since 1871 · Washington Reagan National Airport, 15 mi north-northeast

Mason Neck has a humid subtropical climate. Summer afternoons average 90° in July; winter nights fall to about 30° in January. A normal year brings about 14 inches of snow; with the rain, that comes to about 42 inches of water.

45°30°48°32°57°39°68°48°77°58°85°68°90°72°88°71°81°64°69°52°58°42°49°35° JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 123 TODAY MASON NECK 41.8 in rain and snowmelt
Normal high to low, by month Record high to low, by day Rain by month Freezing
July, average90° / 72°high / low, the warmest month
January, average45° / 30°high / low, the coldest month
Rain and melted snow41.8 inwettest months: July and June
Snow a year13.7 insnowiest: February
Hottest on record106°FJuly 20, 1930
Coldest on record−15°FFebruary 11, 1899
Wettest day on record6.39 inAugust 23, 1933
Snowiest day on record21.0 inJanuary 28, 1922
90° days a year40about 1 of them 100° or more
Nights at or below 32°60and 7 days that stay below freezing
Climate typeHumid subtropicalKöppen Cfa

AROUND THE RING

1Freeze seasonfrom the first fall freeze, about Nov. 17, to the last in spring, about March 25 (median dates)
2Highs of 90° and upJuly 6 to July 27; normal highs reach 90°
3Lows below freezingDec. 27 to Feb. 19; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Mason Neck normally reaches 59° and falls to 42°. The record high is 77°, in 1985; the record low 19°, in 1920. The most rain on this date, 1.56 in, fell in 1972.

MONTH BY MONTH
JanFebMarAprMayJunJulAugSepOctNovDec
Normal high45°48°57°68°77°85°90°88°81°69°58°49°
Normal low30°32°39°48°58°68°72°71°64°52°42°35°
Rain and melt, in2.862.623.503.213.944.204.333.253.933.662.913.41
Snow, inches4.95.02.00.00.00.00.00.00.00.00.11.7
Record high80° (2024)84° (1930)93° (1907)95° (2002)99° (1991)104° (2012)106° (1930)106° (1918)104° (1881)98° (2019)86° (1974)79° (1998)
Record low−14° (1881)−15° (1899)4° (1873)15° (1923)33° (1906)43° (1897)52° (1933)49° (1986)36° (1904)26° (1917)11° (1929)−13° (1880)

Normals 1991–2020 and records since 1871 from the Washington Area threaded record (Washington Reagan National Airport, 15 miles north-northeast). NOAA, through RCC-ACIS.

MILE7
ON THE NETWORK

Around Mason Neck on the Forecast Network

Neighboring plates

Arlington VA · 16 MI 16 miles north Washington DC · 19 MI 19 miles northeast Baltimore MD · 54 MI 54 miles northeast Virginia Beach VA · 144 MI 144 miles southeast Philadelphia PA · 144 MI 144 miles northeast Pittsburgh PA · 194 MI 194 miles northwest
FORECASTCITY
Map of Mason Neck, Virginia. Explore the plate
VIRGINIA · FAIRFAX

Mason Neck

2,025 people, 40 ft above sea level in Fairfax County.

40 ftElevation
2,025People
14 sq miLand
Clear 47°
ClearDew point 30°
1

Today in Mason Neck

NEXT 15 HOURS
Now mostly cloudy night 46° 0%
9p partly cloudy night 43° 1%
12a mostly clear night 40° 1%
3a mostly clear night 40° 1%
6a partly cloudy night 39° 1%
9a partly cloudy day 46° 1%
Clear
NEXT RAINNone this week
→
Sat0%
Partly cloudy Partly cloudy
36
46
A
Sun0%
Mostly cloudy; warmer Mostly cloudy; warmer
33
54
A
Mon0%
Mostly sunny Mostly sunny
31
57
B
Tue0%
Sunny Sunny
31
60
A
Wed0%
Sunny Sunny
32
63
B
Thu0%
Mostly sunny Mostly sunny
36
65
B
Fri0%
Mostly sunny Mostly sunny
38
67
B
Letters show how sure the forecast is: A, models agree; B, some spread; C, check back. Sample data.
THIS WEEK IN 1993 · NOV. 15, 1993

83°, the hottest this week of the year has been since 1871.

2

What Mason Neck stands on

Mason Neck’s center stands about 40 ft above sea level. Within three miles the land runs from 0 ft to 160 ft, a difference of 160 ft: gently rolling country. Open water lies within three miles. The highest named summit within 15 miles is Munson Hill, about 370 ft, 15 miles north.

Mason Neck, northwest to southeast Mason Neck40 ftPotomac Riversea level ← NWSE → 24 miles through the town center; vertical exaggeration about 87×. Colors: rock at the surface.
Elevation, center40 ft
Within 3 miles0 to 160 ft
Lie of the landGently rolling (160 ft of relief)
High point nearbyMunson Hill, 370 ft, 15 mi north
Rock at the surfaceShirley Formation
Its ageQuaternary, less than 2.6 million years old
5

Mason Neck’s year

Mason Neck has a humid subtropical climate. Summer afternoons average 90° in July; winter nights fall to about 30° in January. A normal year brings about 14 inches of snow; with the rain, that comes to about 42 inches of water.

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC 123 41.8 in
July, average90° / 72° · high / low, the warmest month
January, average45° / 30° · high / low, the coldest month
Rain and melted snow41.8 in · wettest months: July and June
Snow a year13.7 in · snowiest: February
Hottest on record106°F · July 20, 1930
Coldest on record−15°F · February 11, 1899
Wettest day on record6.39 in · August 23, 1933
Snowiest day on record21.0 in · January 28, 1922
90° days a year40 · about 1 of them 100° or more
Nights at or below 32°60 · and 7 days that stay below freezing
Climate typeHumid subtropical · Köppen Cfa
1Freeze season · from the first fall freeze, about Nov. 17, to the last in spring, about March 25 (median dates)
2Highs of 90° and up · July 6 to July 27; normal highs reach 90°
3Lows below freezing · Dec. 27 to Feb. 19; normal lows fall below 32°
NOVEMBER 14 IN THE RECORD

On November 14 Mason Neck normally reaches 59° and falls to 42°. The record high is 77°, in 1985; the record low 19°, in 1920. The most rain on this date, 1.56 in, fell in 1972.

Normals 1991–2020 and records since 1871 from the Washington Area threaded record (Washington Reagan National Airport, 15 miles north-northeast). NOAA, through RCC-ACIS.
3

Where the rain goes

≈ 95 mito the AtlanticKanes Creek → Potomac

A raindrop that lands in Mason Neck reaches Chesapeake Bay and the Atlantic Ocean by way of Kanes Creek and the Potomac: about 95 river miles.