Freeze Warning — Jefferson, IL, Wayne, IL, Perry, IL, Franklin, IL, Hamilton, IL, Jackson, IL, Williamson, IL, Saline, IL, Union, IL, Perry, MO, Bollinger, MO, Cape Girardeau, MO, Wayne, MO, Carter, MO, Ripley, MO, Butler, MO, Stoddard, MO 8:00 AM

Williamson County, Illinois, United States

Last updated: 1:20 PM CDT  ·  Refresh
13°C
Feels like 8°
Mostly Cloudy
▲ 13°  /  ▼ 1°
Wind
12 mph NNW
Humidity
58%
Dew Point
5°
Pressure
29.66 inHg
Visibility
10 mi
UV Index
4.7
Cloud Cover
71%
Sunrise
6:25 AM
Sunset
4:51 PM
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WeatherAI™ Analysis

WeatherAI Analysis: Williamson County is currently mostly cloudy at 13°C. Dry conditions are expected through the next 24 hours. Sunrise: 6:25AM · Sunset: 4:51PM.

29 AQI · Good Dominant: O3 Air Quality
Hourly Forecast · Next 24 Hours
Now
13°
0%
2 PM
13°
0%
3 PM
13°
0%
4 PM
13°
0%
5 PM
12°
0%
6 PM
11°
0%
7 PM
10°
0%
8 PM
7°
0%
9 PM
6°
0%
10 PM
5°
0%
11 PM
5°
0%
12 AM
4°
0%
1 AM
3°
0%
2 AM
2°
0%
3 AM
2°
0%
4 AM
2°
0%
5 AM
1°
0%
6 AM
1°
0%
7 AM
2°
0%
8 AM
3°
0%
9 AM
6°
0%
10 AM
7°
0%
11 AM
8°
0%
12 PM
11°
0%
7-Day Forecast
Today
13° 1°
Partly Cloudy.
Sat
14° 1°
Mostly Clear.
Sun
18° 4°
Clear.
Mon
20° 7°
Clear.
Tue
21° 8°
Clear with a 30% chance of rain.
Wed
18° 7°
Mostly Clear with a 41% chance of rain.
Thu
13° 3°
Mostly Cloudy with a 38% chance of rain.
TimeTempConditionsPrecipWindHumidity
Now 13° Mostly Cloudy 0% 12 mph NNW 58%
2 PM 13° Partly Cloudy 0% 12 mph NNW 55%
3 PM 13° Partly Cloudy 0% 11 mph NNW 54%
4 PM 13° Partly Cloudy 0% 10 mph NNW 56%
5 PM 12° Partly Cloudy 0% 8 mph NNW 60%
6 PM 11° Partly Cloudy 0% 7 mph NNW 64%
7 PM 10° Mostly Clear 0% 6 mph N 67%
8 PM 7° Clear 0% 5 mph N 69%
9 PM 6° Clear 0% 5 mph NNW 71%
10 PM 5° Clear 0% 4 mph NNW 74%
11 PM 5° Clear 0% 4 mph NNW 78%
12 AM 4° Clear 0% 4 mph NNW 82%
1 AM 3° Clear 0% 3 mph NNW 85%
2 AM 2° Clear 0% 3 mph NNW 88%
3 AM 2° Clear 0% 3 mph NNW 89%
4 AM 2° Clear 0% 2 mph NNW 90%
5 AM 1° Clear 0% 2 mph NW 90%
6 AM 1° Clear 0% 2 mph NW 91%
7 AM 2° Clear 0% 3 mph NNW 88%
8 AM 3° Clear 0% 3 mph NNW 80%
9 AM 6° Mostly Clear 0% 4 mph NNW 70%
10 AM 7° Mostly Clear 0% 4 mph NNW 63%
11 AM 8° Mostly Clear 0% 4 mph NNW 58%
12 PM 11° Partly Cloudy 0% 5 mph NNW 55%
15-Day Forecast
Today
11/6
Partly Cloudy
0%
1°
13°
Sat
11/7
Mostly Clear
0%
1°
14°
Sun
11/8
Clear
3%
4°
18°
Mon
11/9
Clear
3%
7°
20°
Tue
11/10
Clear
30%
8°
21°
Wed
11/11
Mostly Clear
41%
7°
18°
Thu
11/12
Mostly Cloudy
38%
3°
13°
Fri
11/13
Mostly Cloudy
30%
0°
10°
Sat
11/14
Mostly Clear
25%
-2°
11°
Sun
11/15
Partly Cloudy
50%
-2°
13°
Mon
11/16
Overcast
73%
2°
16°
Tue
11/17
Drizzle
81%
8°
16°
Wed
11/18
Drizzle
78%
8°
16°
Thu
11/19
Drizzle
70%
7°
15°
Fri
11/20
Drizzle
67%
7°
14°
29
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
28 AQI 5.1 µg/m³
O3
Ground-level ozone
Dominant
29 AQI 31 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Sat 29 Good 29 28
Sun 39 Good 29 39
Mon 49 Good 31 49
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 LCLLFCEL0°C Temperature (°C) Pressure (hPa)
Temp Dewpoint Parcel (SB) CAPE CIN Dry adiabat Moist adiabat Mixing ratio
RAP
Valid Fri Nov 6, 18:00'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
SBCAPE78 J/kg
MLCAPE14 J/kg
MUCAPE0 J/kg
SBCIN0 J/kg
MLCIN-1 J/kg
Lifted Index11.6
Kinematics
0–6 km Shear16 kt
0–1 km Shear6 kt
Eff. Shear—
0–1 km SRH8
0–3 km SRH40
Eff. SRH—
Storm Motion344° @ 30 kt
0–1 km EHI0.0
Composite Parameters
Sig. Tornado0.0
STP (eff)—
Supercell—
K-Index-20.5
Thermo & Levels
PWAT0.37 in
0–3 km LR3.5 °C/km
700–500 LR7.4 °C/km
Total Totals29.9
LCL891 hPa
LFC1004 hPa
EL861 hPa
Freezing Lvl10,955 ft