Johnson County, IL Weather Forecast
County weather hub
Mostly Sunny
Compare major city weather across Johnson County, scan the latest forecast snapshots, and jump into local 7-day outlook pages from one hub.
Mostly sunny, with a high near 90. South wind 3 to 14 mph, with gusts as high as 24 mph.
County Weather Overview
This county weather page brings together forecast coverage for Johnson County so visitors can compare temperatures, wind, and conditions across the region without hopping between unrelated pages.
Current forecast coverage spans 3 of 3 mapped cities in Johnson County.
Page Snapshot
- Page focus
- county weather
- Forecast window
- May 17 to May 19, 2026
- Latest sync
- May 13, 2026 10:45 AM CDT
- Forecast office
- PAH
- Source
- NOAA / NWS
Daily Outlook
This Week in Johnson County
Monday looks like the warmest upcoming period in Johnson County at 92 degrees F.
Tuesday Night is the coolest period ahead with temperatures near 65 degrees F.
The strongest winds are forecast for Monday at about 6 to 15 mph S.
Precipitation is mentioned in 4 upcoming forecast periods.
Forecast Details
- Last updated
- May 13, 2026 10:45 AM CDT
- Coverage
- 3 days
- Time zone
- America/Chicago
- Forecast office
- PAH
- Radar station
- KPAH
Weather data is provided by the National Weather Service and refreshed automatically for U.S. locations.
Open NOAA sourceExtended Forecast
Mostly clear, with a low around 69. South wind 6 to 10 mph, with gusts as high as 21 mph.
A slight chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 92. South wind 6 to 15 mph, with gusts as high as 25 mph.
A slight chance of showers and thunderstorms before 7pm, then a chance of showers and thunderstorms. Partly cloudy, with a low around 69. South wind 7 to 12 mph, with gusts as high as 22 mph.
Showers and thunderstorms likely. Partly sunny, with a high near 86. South southwest wind 7 to 14 mph, with gusts as high as 24 mph.
Showers and thunderstorms likely. Mostly cloudy, with a low around 65. Southwest wind 2 to 9 mph, with gusts as high as 18 mph.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Sunday
May 17
|
Mostly Sunny
|
90°F |
3 to 14 mph
S
|
|
Sunday Night
May 17
|
Mostly Clear
|
69°F |
6 to 10 mph
S
|
|
Monday
May 18
|
Mostly Sunny then Slight Chance Showers And Thunderstorms
|
92°F |
6 to 15 mph
S
|
|
Monday Night
May 18
|
Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms
|
69°F |
7 to 12 mph
S
|
|
Tuesday
May 19
|
Showers And Thunderstorms Likely
|
86°F |
7 to 14 mph
SSW
|
|
Tuesday Night
May 19
|
Showers And Thunderstorms Likely
|
65°F |
2 to 9 mph
SW
|
Major City Forecasts
Live forecast snapshots for major cities across Johnson County.
Coverage
Forecast coverage currently spans 3 of 3 mapped cities in Johnson County.
Largest mapped city population in this region: 1,427.
