Loudoun County, Virginia, United States

Last updated: 9:10 PM CDT  ·  Refresh
21°C
Feels like 20°
Partly Cloudy
▲ 29°  /  ▼ 16°
Wind
9 mph N
Humidity
84%
Dew Point
17°
Pressure
29.53 inHg
Visibility
10 mi
UV Index
0.0
Cloud Cover
36%
Sunrise
6:28 AM
Sunset
7:58 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Loudoun County is currently partly cloudy at 20°C. Dry conditions are expected through the next 24 hours. Sunrise: 6:28AM · Sunset: 7:58PM.

Alerts

No active alerts for this location.
38 AQI · Good Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
21°
3%
11 PM
19°
21%
12 AM
19°
21%
1 AM
18°
14%
2 AM
18°
3%
3 AM
17°
3%
4 AM
17°
3%
5 AM
17°
15%
6 AM
16°
15%
7 AM
16°
3%
8 AM
17°
3%
9 AM
18°
3%
10 AM
20°
3%
11 AM
21°
3%
12 PM
22°
3%
1 PM
24°
3%
2 PM
26°
5%
3 PM
27°
18%
4 PM
27°
22%
5 PM
27°
22%
6 PM
25°
32%
7 PM
24°
32%
8 PM
23°
33%
9 PM
22°
36%
7-Day Forecast
Tonight
29° 16°
Partly Cloudy.
Fri
27° 16°
Partly Cloudy with a 36% chance of rain.
Sat
24° 18°
Rain, 78% chance.
Sun
30° 17°
Partly Cloudy with a 39% chance of rain.
Mon
29° 16°
Clear.
Tue
30° 15°
Rain, 61% chance.
Wed
31° 17°
Rain, 71% chance.
TimeTempConditionsPrecipWindHumidity
Now 21° Partly Cloudy 3% 9 mph N 84%
11 PM 19° Mostly Clear 21% 8 mph N 87%
12 AM 19° Mostly Clear 21% 6 mph N 90%
1 AM 18° Partly Cloudy 14% 5 mph N 92%
2 AM 18° Partly Cloudy 3% 3 mph NNW 93%
3 AM 17° Partly Cloudy 3% 4 mph NNW 94%
4 AM 17° Mostly Cloudy 3% 5 mph NNW 94%
5 AM 17° Partly Cloudy 15% 6 mph NNW 95%
6 AM 16° Mostly Cloudy 15% 5 mph NNW 93%
7 AM 16° Mostly Cloudy 3% 5 mph NNW 91%
8 AM 17° Mostly Cloudy 3% 6 mph N 86%
9 AM 18° Partly Cloudy 3% 6 mph N 80%
10 AM 20° Partly Cloudy 3% 6 mph N 74%
11 AM 21° Partly Cloudy 3% 6 mph N 68%
12 PM 22° Partly Cloudy 3% 5 mph NNE 64%
1 PM 24° Partly Cloudy 3% 4 mph NE 59%
2 PM 26° Partly Cloudy 5% 4 mph ENE 55%
3 PM 27° Partly Cloudy 18% 4 mph ENE 53%
4 PM 27° Mostly Clear 22% 4 mph ENE 52%
5 PM 27° Mostly Clear 22% 4 mph E 53%
6 PM 25° Mostly Clear 32% 4 mph ENE 58%
7 PM 24° Mostly Clear 32% 3 mph ENE 63%
8 PM 23° Partly Cloudy 33% 3 mph ENE 68%
9 PM 22° Partly Cloudy 36% 3 mph ENE 70%
15-Day Forecast
Today
8/20
Partly Cloudy
3%
16°
29°
Fri
8/21
Partly Cloudy
36%
16°
27°
Sat
8/22
Rain
78%
18°
24°
Sun
8/23
Partly Cloudy
39%
17°
30°
Mon
8/24
Clear
3%
16°
29°
Tue
8/25
Rain
61%
15°
30°
Wed
8/26
Rain
71%
17°
31°
Thu
8/27
Rain
82%
18°
29°
Fri
8/28
Rain
68%
18°
32°
Sat
8/29
Drizzle
68%
18°
32°
Sun
8/30
Drizzle
60%
19°
32°
Mon
8/31
Drizzle
60%
18°
31°
Tue
9/1
Drizzle
60%
17°
30°
Wed
9/2
Drizzle
60%
17°
30°
Thu
9/3
Drizzle
60%
17°
29°
38
Good
U.S. Air Quality Index · Dominant: PM2.5
50 100 150 200

Air quality is satisfactory and poses little or no health risk.

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
Dominant
38 AQI 6.8 µg/m³
O3
Ground-level ozone
34 AQI 37 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 38 Good 34 38
Sat 41 Good 41 35
Sun 37 Good 37 29
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
MLCAPE23 J/kg
MUCAPE0 J/kg
SBCIN—
MLCIN0 J/kg
Lifted Index4.7
Kinematics
0–6 km Shear36 kt
0–1 km Shear14 kt
Eff. Shear—
0–1 km SRH-75
0–3 km SRH4
Eff. SRH—
Storm Motion314° @ 29 kt
0–1 km EHI-0.0
Composite Parameters
Sig. Tornado0.0
STP (eff)—
Supercell—
K-Index30.2
Thermo & Levels
PWAT1.64 in
0–3 km LR4.2 °C/km
700–500 LR5.4 °C/km
Total Totals40.9
LCL955 hPa
LFC—
EL—
Freezing Lvl14,426 ft