Fairfax County, Virginia, United States

Last updated: 9:10 PM CDT  ·  Refresh
21°C
Feels like 21°
Mostly Clear
▲ 31°  /  ▼ 17°
Wind
10 mph N
Humidity
78%
Dew Point
18°
Pressure
29.64 inHg
Visibility
9 mi
UV Index
0.0
Cloud Cover
27%
Sunrise
6:27 AM
Sunset
7:56 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Fairfax County is currently mostly clear at 21°C. Dry conditions are expected through the next 24 hours. Sunrise: 6:27AM · Sunset: 7:56PM.

Alerts

No active alerts for this location.
51 AQI · Moderate Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
21°
4%
11 PM
20°
23%
12 AM
20°
23%
1 AM
19°
14%
2 AM
19°
3%
3 AM
18°
3%
4 AM
18°
3%
5 AM
17°
3%
6 AM
17°
3%
7 AM
17°
3%
8 AM
18°
3%
9 AM
19°
6%
10 AM
21°
6%
11 AM
22°
8%
12 PM
23°
8%
1 PM
25°
8%
2 PM
26°
8%
3 PM
26°
17%
4 PM
27°
32%
5 PM
26°
32%
6 PM
26°
32%
7 PM
24°
36%
8 PM
24°
36%
9 PM
22°
40%
7-Day Forecast
Tonight
31° 17°
Mostly Clear.
Fri
28° 17°
Partly Cloudy with a 40% chance of rain.
Sat
25° 20°
Overcast with a 71% chance of rain.
Sun
31° 19°
Overcast with a 28% chance of rain.
Mon
30° 18°
Clear.
Tue
31° 18°
Rain, 61% chance.
Wed
31° 19°
Heavy Rain, 82% chance.
TimeTempConditionsPrecipWindHumidity
Now 21° Mostly Clear 4% 10 mph N 78%
11 PM 20° Partly Cloudy 23% 9 mph N 80%
12 AM 20° Partly Cloudy 23% 7 mph N 81%
1 AM 19° Partly Cloudy 14% 5 mph N 82%
2 AM 19° Partly Cloudy 3% 5 mph N 83%
3 AM 18° Partly Cloudy 3% 5 mph NNW 84%
4 AM 18° Partly Cloudy 3% 6 mph NNW 85%
5 AM 17° Partly Cloudy 3% 6 mph NNW 88%
6 AM 17° Partly Cloudy 3% 6 mph NNW 87%
7 AM 17° Mostly Cloudy 3% 6 mph N 86%
8 AM 18° Mostly Cloudy 3% 7 mph N 83%
9 AM 19° Partly Cloudy 6% 6 mph N 77%
10 AM 21° Mostly Clear 6% 6 mph N 69%
11 AM 22° Mostly Clear 8% 6 mph N 62%
12 PM 23° Partly Cloudy 8% 4 mph N 61%
1 PM 25° Partly Cloudy 8% 3 mph NNE 59%
2 PM 26° Mostly Cloudy 8% 3 mph ENE 58%
3 PM 26° Partly Cloudy 17% 3 mph ENE 55%
4 PM 27° Partly Cloudy 32% 3 mph ENE 54%
5 PM 26° Mostly Clear 32% 3 mph ENE 53%
6 PM 26° Partly Cloudy 32% 3 mph ENE 58%
7 PM 24° Partly Cloudy 36% 4 mph E 62%
8 PM 24° Mostly Cloudy 36% 4 mph E 66%
9 PM 22° Overcast 40% 4 mph E 68%
15-Day Forecast
Today
8/20
Mostly Clear
4%
17°
31°
Fri
8/21
Partly Cloudy
40%
17°
28°
Sat
8/22
Overcast
71%
20°
25°
Sun
8/23
Overcast
28%
19°
31°
Mon
8/24
Clear
3%
18°
30°
Tue
8/25
Rain
61%
18°
31°
Wed
8/26
Heavy Rain
82%
19°
31°
Thu
8/27
Rain
82%
19°
29°
Fri
8/28
Drizzle
44%
20°
32°
Sat
8/29
Rain
68%
21°
33°
Sun
8/30
Clear
60%
20°
33°
Mon
8/31
Drizzle
60%
20°
32°
Tue
9/1
Drizzle
60%
19°
31°
Wed
9/2
Drizzle
60%
18°
31°
Thu
9/3
Drizzle
60%
18°
30°
51
Moderate
U.S. Air Quality Index · Dominant: PM2.5
50 100 150 200

Air quality is acceptable. Unusually sensitive people should consider limiting prolonged outdoor exertion.

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
Dominant
51 AQI 9.1 µg/m³
O3
Ground-level ozone
37 AQI 40 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 51 Moderate 37 51
Sat 39 Good 39 33
Sun 40 Good 40 31
About the Air Quality Index
0–50 Good
51–100 Moderate
101–150 Unhealthy for Sensitive Groups
151–200 Unhealthy
201–300 Very Unhealthy
301–500 Hazardous

The U.S. AQI runs 0–500. The overall value equals the highest individual pollutant sub-index, and the dominant pollutant is the one driving it. PM2.5 (fine particles) is reported in µg/m³ and ozone (O3) in ppb. Forecast source: NWS NAQFC.

1000850700500400300250200150100 -40-30-20-10010203040 0.41247101624 LCL0°C Temperature (°C) Pressure (hPa)
Temp Dewpoint Parcel (SB) CAPE CIN Dry adiabat Moist adiabat Mixing ratio
RAP
Valid Thu Aug 20, 23:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 50 60 70 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE0 J/kg
MLCAPE10 J/kg
MUCAPE0 J/kg
SBCIN—
MLCIN0 J/kg
Lifted Index4.1
Kinematics
0–6 km Shear35 kt
0–1 km Shear14 kt
Eff. Shear—
0–1 km SRH-75
0–3 km SRH-7
Eff. SRH—
Storm Motion303° @ 30 kt
0–1 km EHI-0.0
Composite Parameters
Sig. Tornado0.0
STP (eff)—
Supercell—
K-Index32.3
Thermo & Levels
PWAT1.74 in
0–3 km LR4.5 °C/km
700–500 LR5.0 °C/km
Total Totals41.0
LCL959 hPa
LFC—
EL—
Freezing Lvl14,478 ft