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Great Falls, Virginia

Community in Fairfax County, Virginia

Air quality

The air at Great Falls

Index 22, good, led by fine particles. Read at 11 PM from its reporting area, Northern Virginia (VA), 10 miles off.

22Good
  • Fine particles (PM2.5)22Good13.9 mi
  • Ozone16Good11 ppb13.9 mi
  • Coarse particles (PM10)7Good-
  • Nitrogen dioxide4Good4.2 ppb24 mi
  • Sulfur dioxide0Good0 ppb24 mi
  • Carbon monoxide-0.1 ppm24 mi

The days ahead

Good each day through Sun Oct 18, led by fine particles. Yesterday measured 52, moderate.

Smoke, the next 46 hours

Little smoke near the ground through Sat 8 PM: the index from smoke stays at 6 or under.

FriSat

Precipitation

What has fallen at Great Falls

None in the last 3 days, to Thu 10 PM. Measured by radar and rain gauges, as water.

Last 24 hours
0.00in
Last 3 days
0.00in

Visibility

How far you can see at Great Falls, the next 46 hours

Visibility stays 7 miles or more through Sat 8 PM, lowest 8 miles Fri 5 AM.

FriSat

On the radar over Great Falls, VirginiaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 5 instruments nearest Great Falls, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 0.5 miles away.

measured now3 instruments

measured daily2 instruments

Reston 1.8 NVA-FX-76

In a volunteer observer's own ground/2.4 mi away/445 ft/106 ft above here

precip, snowfall, snow depth

Rank-

Dunn LoringDNLV2

At a cooperative observer's station/9.0 mi away/489 ft/150 ft above here

snowfall, snow depth, precip, high, low

Rank1,540of 1,541

Station report

The weather at Washington/Dulles, drawn

The nearest airport reporting now, 8.5 mi from Great Falls, Virginia. From its report of Oct 15, 2026, 10:52 PM local time: 3 of its 6 sheets.

The sky

Broken at 1,500 ft, overcast at 2,100 ft; the ceiling is 1,500 ft; visibility 4 mi.

Section of the sky over Washington/Dulles, height above the station to scale: broken cloud with its base at 1,500 feet, overcast cloud with its base at 2,100 feet, the ceiling at 1,500 feet, and visibility of 4 mi.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT IADFIG. A THE SKY OVER WASHINGTON/DULLESSECTION, HEIGHT ABOVE THE STATION TO SCALE, EACH LAYER AT THE HEIGHT OF ITS BASE AS REPORTED; COVER IN EIGHTHS OF THE SKY; TOPS NOT MEASUREDFT ABOVE THE STATION05001,0001,5002,0002,5003,0003,500ETAGESLOWTHE STATIONTHE CEILOMETER READS TO 12,000 FT, ABOVE THIS SHEETOVC 2,100 FTOVERCAST, 8 EIGHTHS OF THE SKYBKN 1,500 FTBROKEN, 5 TO 7 EIGHTHS OF THE SKYCEILING 1,500 FTVISIBILITY, MILES: 4 MI0510TITLEWashington/Dulles, the skySTATION REPORT · ASOS IADTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-IAD-1DRAWN AS linework on paperSOURCES FB-SKY-001, FB-SKY-017, FB-SKY-016, FB-SKY-018

The air

59.0 F with a dew point of 58.0 F, 96 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 200 ft up; the lowest cloud reported is at 1,500 ft.

Chart of the air at Washington/Dulles: temperature 59.0 degrees Fahrenheit and dew point 58.0, 96 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 200 feet above the station, against the lowest cloud reported at 1,500 feet; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT IADFIG. B THE AIR AT WASHINGTON/DULLESTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00050 F60 F70 FSATURATES 200 FT ABOVE THE STATION, AT 57.7 FLOWEST CLOUD REPORTED, BKN 1,500 FTTEMPERATURE AND DEW POINT 59.0 F, 58.0 FRELATIVE HUMIDITY 96 PER CENTTHE AIR COOLS ABOUT 5.4 F EACH 1,000 FT IT RISES, AND ITS DEW POINT ABOUT 1 FSOLID: THE LIFTED AIR'S TEMPERATURE; DASHED: ITS DEW POINTTITLEWashington/Dulles, the airSTATION REPORT · ASOS IADTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-IAD-2DRAWN AS linework on paperSOURCES FB-WAT-020, FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the southeast (140 degrees) at 3 mph: force 1, a light air on the Beaufort scale. The strongest gust today was 21 mph.

Plan of the wind at Washington/Dulles, north up: blowing from 140 degrees, the southeast, at 3 miles an hour; beside it the Beaufort scale from calm to hurricane force, force 1, light air, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT IADFIG. C THE WIND AT WASHINGTON/DULLESPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 140°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR1NOW, 3 MPH2LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLEWashington/Dulles, the windSTATION REPORT · ASOS IADTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-IAD-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Washington/Dulles, in 6 sheets, each beside the Field Book plates that explain it

0in

Snow on the ground

Measured at Dunn Loring (DNLV2), 9.0 miles from here, read 15 Oct, 08:00. measured daily

Elsewhere in Virginia

16 places, each with its own forecast and its own instruments.

Near Great Falls

The nearest places, each with its own forecast and the instruments nearest it.

Near Great Falls

River and lake gauges