Loudoun County, Virginia, United States

Last updated: 2:19 AM CDT  ·  Refresh
4°C
Feels like 3°
Clear
▲ 19°  /  ▼ 5°
Wind
5 mph NW
Humidity
77%
Dew Point
2°
Pressure
29.60 inHg
Visibility
10 mi
UV Index
0.0
Cloud Cover
0%
Sunrise
7:27 AM
Sunset
6:22 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Loudoun County is currently clear at 5°C. Dry conditions are expected through the next 24 hours. Sunrise: 7:27AM · Sunset: 6:22PM.

Alerts

No active alerts for this location.
32 AQI · Good Dominant: O3 Air Quality
Hourly Forecast · Next 24 Hours
Now
4°
3%
4 AM
5°
3%
5 AM
3°
3%
6 AM
3°
3%
7 AM
3°
3%
8 AM
4°
3%
9 AM
7°
3%
10 AM
11°
3%
11 AM
13°
3%
12 PM
14°
3%
1 PM
18°
3%
2 PM
19°
3%
3 PM
19°
3%
4 PM
19°
3%
5 PM
17°
3%
6 PM
15°
3%
7 PM
13°
3%
8 PM
12°
3%
9 PM
11°
3%
10 PM
9°
3%
11 PM
9°
3%
12 AM
9°
3%
1 AM
9°
3%
2 AM
9°
3%
7-Day Forecast
Today
19° 5°
Clear.
Fri
19° 4°
Mostly Clear.
Sat
20° 1°
Mostly Clear.
Sun
17° 2°
Fog.
Mon
23° 4°
Clear.
Tue
22° 8°
Clear.
Wed
23° 7°
Clear.
TimeTempConditionsPrecipWindHumidity
Now 4° Clear 3% 5 mph NW 77%
4 AM 5° Clear 3% 6 mph NW 76%
5 AM 3° Clear 3% 7 mph NW 77%
6 AM 3° Clear 3% 7 mph NW 76%
7 AM 3° Clear 3% 8 mph NW 75%
8 AM 4° Clear 3% 8 mph NW 71%
9 AM 7° Clear 3% 8 mph NW 61%
10 AM 11° Clear 3% 10 mph NNW 51%
11 AM 13° Clear 3% 11 mph NNW 43%
12 PM 14° Clear 3% 11 mph NNW 40%
1 PM 18° Clear 3% 11 mph NNW 36%
2 PM 19° Clear 3% 11 mph NNW 35%
3 PM 19° Clear 3% 11 mph NNW 38%
4 PM 19° Clear 3% 10 mph NNW 41%
5 PM 17° Clear 3% 9 mph NNW 45%
6 PM 15° Clear 3% 7 mph NNW 50%
7 PM 13° Clear 3% 7 mph NNW 55%
8 PM 12° Clear 3% 6 mph NW 60%
9 PM 11° Clear 3% 6 mph NW 64%
10 PM 9° Clear 3% 6 mph NNW 67%
11 PM 9° Clear 3% 6 mph NNW 70%
12 AM 9° Clear 3% 6 mph NNW 73%
1 AM 9° Clear 3% 6 mph NNW 75%
2 AM 9° Clear 3% 6 mph NNW 78%
15-Day Forecast
Today
10/22
Clear
3%
5°
19°
Fri
10/23
Mostly Clear
3%
4°
19°
Sat
10/24
Mostly Clear
3%
1°
20°
Sun
10/25
Fog
3%
2°
17°
Mon
10/26
Clear
3%
4°
23°
Tue
10/27
Clear
3%
8°
22°
Wed
10/28
Clear
8%
7°
23°
Thu
10/29
Clear
18%
7°
19°
Fri
10/30
Clear
3%
3°
20°
Sat
10/31
Clear
42%
4°
20°
Sun
11/1
Drizzle
60%
9°
20°
Mon
11/2
Drizzle
60%
11°
20°
Tue
11/3
Drizzle
60%
9°
19°
Wed
11/4
Drizzle
60%
8°
18°
Thu
11/5
Drizzle
60%
8°
19°
32
Good
U.S. Air Quality Index · Dominant: O3
50 100 150 200

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

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
15 AQI 2.7 µg/m³
O3
Ground-level ozone
Dominant
32 AQI 36 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 32 Good 32 15
Fri 34 Good 34 14
Sat 31 Good 31 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 Oct 22, 06:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE0 J/kg
MLCAPE13 J/kg
MUCAPE0 J/kg
SBCIN—
MLCIN0 J/kg
Lifted Index21.7
Kinematics
0–6 km Shear10 kt
0–1 km Shear17 kt
Eff. Shear—
0–1 km SRH-23
0–3 km SRH5
Eff. SRH—
Storm Motion348° @ 24 kt
0–1 km EHI-0.0
Composite Parameters
Sig. Tornado0.0
STP (eff)—
Supercell—
K-Index-38.2
Thermo & Levels
PWAT0.21 in
0–3 km LR0.6 °C/km
700–500 LR6.8 °C/km
Total Totals11.1
LCL959 hPa
LFC—
EL—
Freezing Lvl11,286 ft