Heat Advisory — Jefferson, IL, Wayne, IL, Edwards, IL, Wabash, IL, Franklin, IL, Hamilton, IL, White, IL, Jackson, IL, Williamson, IL, Saline, IL, Gallatin, IL, Union, IL, Johnson, IL, Pope, IL, Hardin, IL, Alexander, IL, Pulaski, IL, Massac, IL, Gibson, IN, Pike, IN, Posey, IN, Vanderburgh, IN, Warrick, IN, Spencer, IN, Fulton, KY, Hickman, KY, Carlisle, KY, Ballard, KY, McCracken, KY, Graves, KY, Livingston, KY, Marshall, KY, Calloway, KY, Crittenden, KY, Lyon, KY, Trigg, KY, Caldwell, KY, Union, KY, Webster, KY, Hopkins, KY, Christian, KY, Henderson, KY, Daviess, KY, McLean, KY, Muhlenberg, KY, Todd, KY, Perry, MO, Bollinger, MO, Cape Girardeau, MO, Wayne, MO, Carter, MO, Ripley, MO, Butler, MO, Stoddard, MO, Scott, MO, Mississippi, MO, New Madrid, MO 8:00 PM

Johnson County, Illinois, United States

Last updated: 8:05 AM CDT  ·  Refresh
24°C
Feels like 27°
Partly Cloudy
▲ 34°  /  ▼ 23°
Wind
7 mph SSW
Humidity
84%
Dew Point
22°
Pressure
29.56 inHg
Visibility
9 mi
UV Index
5.1
Cloud Cover
30%
Sunrise
6:07 AM
Sunset
7:53 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Johnson County is currently partly cloudy at 25°C. Dry conditions are expected through the next 24 hours. Atmospheric instability is elevated (CAPE up to 3571 J/kg) — isolated convective development possible. Sunrise: 6:07AM · Sunset: 7:53PM.

Alerts

Heat Advisory
Jefferson, IL, Wayne, IL, Edwards, IL, Wabash, IL, Franklin, IL, Hamilton, IL, White, IL, Jackson, IL, Williamson, IL, Saline, IL, Gallatin, IL, Union, IL, Johnson, IL, Pope, IL, Hardin, IL, Alexander, IL, Pulaski, IL, Massac, IL, Gibson, IN, Pike, IN, Posey, IN, Vanderburgh, IN, Warrick, IN, Spencer, IN, Fulton, KY, Hickman, KY, Carlisle, KY, Ballard, KY, McCracken, KY, Graves, KY, Livingston, KY, Marshall, KY, Calloway, KY, Crittenden, KY, Lyon, KY, Trigg, KY, Caldwell, KY, Union, KY, Webster, KY, Hopkins, KY, Christian, KY, Henderson, KY, Daviess, KY, McLean, KY, Muhlenberg, KY, Todd, KY, Perry, MO, Bollinger, MO, Cape Girardeau, MO, Wayne, MO, Carter, MO, Ripley, MO, Butler, MO, Stoddard, MO, Scott, MO, Mississippi, MO, New Madrid, MO
Expires 8:00 PM
40 AQI · Good Dominant: O3 Air Quality
Hourly Forecast · Next 24 Hours
Now
24°
11%
9 AM
26°
14%
10 AM
28°
14%
11 AM
29°
14%
12 PM
31°
14%
1 PM
33°
3%
2 PM
33°
3%
3 PM
33°
3%
4 PM
33°
3%
5 PM
33°
3%
6 PM
32°
3%
7 PM
31°
3%
8 PM
29°
3%
9 PM
27°
3%
10 PM
26°
5%
11 PM
26°
5%
12 AM
26°
5%
1 AM
25°
5%
2 AM
24°
5%
3 AM
24°
5%
4 AM
24°
5%
5 AM
23°
5%
6 AM
23°
5%
7 AM
23°
5%
7-Day Forecast
Today
34° 23°
Partly Cloudy.
Tue
36° 23°
Clear.
Wed
38° 24°
Mostly Clear with a 50% chance of rain.
Thu
36° 24°
Mostly Clear with a 73% chance of rain.
Fri
33° 23°
Partly Cloudy with a 57% chance of rain.
Sat
37° 23°
Clear.
Sun
38° 24°
Clear.
TimeTempConditionsPrecipWindHumidity
Now 24° Partly Cloudy 11% 7 mph SSW 84%
9 AM 26° Mostly Clear 14% 10 mph SW 76%
10 AM 28° Clear 14% 11 mph SW 70%
11 AM 29° Mostly Clear 14% 11 mph SW 65%
12 PM 31° Mostly Clear 14% 12 mph SW 60%
1 PM 33° Partly Cloudy 3% 12 mph SW 56%
2 PM 33° Partly Cloudy 3% 12 mph SW 54%
3 PM 33° Partly Cloudy 3% 12 mph SSW 53%
4 PM 33° Partly Cloudy 3% 12 mph SSW 53%
5 PM 33° Partly Cloudy 3% 10 mph SSW 58%
6 PM 32° Partly Cloudy 3% 8 mph SSW 64%
7 PM 31° Partly Cloudy 3% 7 mph SSW 69%
8 PM 29° Partly Cloudy 3% 6 mph SSW 71%
9 PM 27° Partly Cloudy 3% 6 mph SSW 74%
10 PM 26° Partly Cloudy 5% 6 mph SSW 75%
11 PM 26° Partly Cloudy 5% 7 mph SSW 77%
12 AM 26° Partly Cloudy 5% 7 mph SSW 79%
1 AM 25° Partly Cloudy 5% 7 mph SSW 81%
2 AM 24° Partly Cloudy 5% 7 mph SSW 82%
3 AM 24° Partly Cloudy 5% 7 mph SSW 84%
4 AM 24° Mostly Clear 5% 7 mph SSW 85%
5 AM 23° Mostly Clear 5% 7 mph SSW 85%
6 AM 23° Mostly Clear 5% 8 mph SSW 86%
7 AM 23° Clear 5% 8 mph SSW 86%
15-Day Forecast
Today
8/10
Partly Cloudy
14%
23°
34°
Tue
8/11
Clear
6%
23°
36°
Wed
8/12
Mostly Clear
50%
24°
38°
Thu
8/13
Mostly Clear
73%
24°
36°
Fri
8/14
Partly Cloudy
57%
23°
33°
Sat
8/15
Clear
15%
23°
37°
Sun
8/16
Clear
15%
24°
38°
Mon
8/17
Drizzle
63%
22°
34°
Tue
8/18
Drizzle
66%
19°
35°
Wed
8/19
Clear
44%
21°
34°
Thu
8/20
Drizzle
60%
23°
36°
Fri
8/21
Drizzle
60%
21°
34°
Sat
8/22
Clear
60%
21°
34°
Sun
8/23
Drizzle
60%
21°
35°
Mon
8/24
Clear
60%
20°
33°
40
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
38 AQI 6.9 µg/m³
O3
Ground-level ozone
Dominant
40 AQI 44 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Tue 40 Good 40 38
Wed 37 Good 37 16
Thu 33 Good 33 23
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 Mon Aug 10, 11:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE1523 J/kg
MLCAPE1520 J/kg
MUCAPE1926 J/kg
SBCIN0 J/kg
MLCIN0 J/kg
Lifted Index-6.7
Kinematics
0–6 km Shear8 kt
0–1 km Shear19 kt
Eff. Shear6 kt
0–1 km SRH103
0–3 km SRH119
Eff. SRH119
Storm Motion41° @ 6 kt
0–1 km EHI1.0
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index26.5
Thermo & Levels
PWAT1.58 in
0–3 km LR4.1 °C/km
700–500 LR8.1 °C/km
Total Totals52.9
LCL971 hPa
LFC1001 hPa
EL195 hPa
Freezing Lvl14,715 ft