Johnson County, Illinois, United States

Last updated: 9:59 PM CDT  ·  Refresh
26°C
Feels like 29°
Clear
▲ 34°  /  ▼ 19°
Wind
6 mph N
Humidity
80%
Dew Point
22°
Pressure
29.36 inHg
Visibility
10 mi
UV Index
0.0
Cloud Cover
3%
Sunrise
5:51 AM
Sunset
8:12 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Johnson County is currently clear at 26°C. Dry conditions are expected through the next 24 hours. Sunrise: 5:51AM · Sunset: 8:12PM.

Alerts

No active alerts for this location.
44 AQI · Good Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
26°
3%
10 PM
24°
14%
11 PM
24°
14%
12 AM
23°
3%
1 AM
22°
3%
2 AM
21°
3%
3 AM
21°
3%
4 AM
19°
3%
5 AM
19°
3%
6 AM
19°
3%
7 AM
21°
3%
8 AM
23°
3%
9 AM
24°
3%
10 AM
25°
5%
11 AM
26°
5%
12 PM
28°
5%
1 PM
28°
5%
2 PM
28°
5%
3 PM
28°
3%
4 PM
28°
3%
5 PM
27°
3%
6 PM
27°
3%
7 PM
26°
3%
8 PM
23°
3%
7-Day Forecast
Tonight
34° 19°
Clear.
Wed
29° 17°
Mostly Clear.
Thu
27° 16°
Clear.
Fri
24° 16°
Mostly Cloudy with a 62% chance of rain.
Sat
29° 18°
Clear with a 47% chance of rain.
Sun
33° 23°
Clear.
Mon
34° 22°
Clear.
TimeTempConditionsPrecipWindHumidity
Now 26° Clear 3% 6 mph N 80%
10 PM 24° Clear 14% 7 mph N 83%
11 PM 24° Clear 14% 7 mph N 84%
12 AM 23° Clear 3% 6 mph N 85%
1 AM 22° Clear 3% 6 mph N 87%
2 AM 21° Clear 3% 6 mph N 89%
3 AM 21° Clear 3% 5 mph NNW 91%
4 AM 19° Clear 3% 6 mph NNW 91%
5 AM 19° Clear 3% 6 mph N 90%
6 AM 19° Clear 3% 7 mph N 89%
7 AM 21° Clear 3% 8 mph N 84%
8 AM 23° Clear 3% 7 mph N 81%
9 AM 24° Clear 3% 7 mph N 76%
10 AM 25° Mostly Clear 5% 8 mph N 72%
11 AM 26° Partly Cloudy 5% 9 mph N 68%
12 PM 28° Partly Cloudy 5% 10 mph N 65%
1 PM 28° Partly Cloudy 5% 10 mph NNE 64%
2 PM 28° Partly Cloudy 5% 10 mph NNE 63%
3 PM 28° Partly Cloudy 3% 10 mph NNE 62%
4 PM 28° Partly Cloudy 3% 9 mph NNE 64%
5 PM 27° Partly Cloudy 3% 9 mph NNE 67%
6 PM 27° Partly Cloudy 3% 9 mph NNE 69%
7 PM 26° Partly Cloudy 3% 9 mph NNE 71%
8 PM 23° Partly Cloudy 3% 9 mph NNE 73%
15-Day Forecast
Today
7/21
Clear
3%
19°
34°
Wed
7/22
Mostly Clear
5%
17°
29°
Thu
7/23
Clear
3%
16°
27°
Fri
7/24
Mostly Cloudy
62%
16°
24°
Sat
7/25
Clear
47%
18°
29°
Sun
7/26
Clear
17%
23°
33°
Mon
7/27
Clear
17%
22°
34°
Tue
7/28
Clear
28%
19°
32°
Wed
7/29
Drizzle
44%
18°
29°
Thu
7/30
Drizzle
44%
16°
29°
Fri
7/31
Drizzle
51%
16°
29°
Sat
8/1
Drizzle
60%
18°
30°
Sun
8/2
Clear
60%
19°
31°
Mon
8/3
Drizzle
60%
19°
31°
Tue
8/4
Drizzle
60%
20°
31°
44
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
44 AQI 8.1 µg/m³
O3
Ground-level ozone
31 AQI 35 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 44 Good 31 44
Thu 27 Good 27 18
Fri 31 Good 31 7
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 Wed Jul 22, 01:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 50 60 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE34 J/kg
MLCAPE11 J/kg
MUCAPE34 J/kg
SBCIN-454 J/kg
MLCIN0 J/kg
Lifted Index1.2
Kinematics
0–6 km Shear40 kt
0–1 km Shear13 kt
Eff. Shear—
0–1 km SRH-111
0–3 km SRH-123
Eff. SRH—
Storm Motion281° @ 30 kt
0–1 km EHI-0.0
Composite Parameters
Sig. Tornado0.0
STP (eff)—
Supercell—
K-Index4.4
Thermo & Levels
PWAT1.26 in
0–3 km LR4.5 °C/km
700–500 LR5.3 °C/km
Total Totals36.6
LCL935 hPa
LFC419 hPa
EL251 hPa
Freezing Lvl17,562 ft