Washington County, IL Weather Forecast
County weather hub
Mostly Sunny then Slight Chance Showers And Thunderstorms
Compare major city weather across Washington County, scan the latest forecast snapshots, and jump into local 7-day outlook pages from one hub.
A slight chance of rain showers between noon and 1pm, then a slight chance of showers and thunderstorms. Mostly sunny, with a high near 91. Heat index values as high as 102. West wind 3 to 9 mph. Chance of precipitation is 20%.
County Weather Overview
This county weather page brings together forecast coverage for Washington County so visitors can compare temperatures, wind, and conditions across the region without hopping between unrelated pages.
Current forecast coverage spans 2 of 2 mapped cities in Washington County.
Page Snapshot
- Page focus
- county weather
- Forecast window
- Jul 18 to Jul 24, 2026
- Latest sync
- Jul 18, 2026 8:25 AM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in Washington County
Tuesday looks like the warmest upcoming period in Washington County at 93 degrees F.
Wednesday Night is the coolest period ahead with temperatures near 62 degrees F.
The strongest winds are forecast for Tuesday at about 6 to 12 mph W.
Precipitation is mentioned in 8 upcoming forecast periods.
Forecast Details
- Last updated
- Jul 18, 2026 8:25 AM CDT
- Coverage
- 7 days
- Time zone
- America/Chicago
- Forecast office
- LSX
- Radar station
- KLSX
Weather data is provided by the National Weather Service and refreshed automatically for U.S. locations.
Open NOAA sourceExtended Forecast
A slight chance of showers and thunderstorms before 3am. Partly cloudy, with a low around 73. West wind 1 to 7 mph. Chance of precipitation is 20%.
A chance of showers and thunderstorms after noon. Mostly sunny, with a high near 89. Heat index values as high as 100. North wind around 2 mph. Chance of precipitation is 40%.
A chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 70. Northeast wind around 2 mph. Chance of precipitation is 30%.
Mostly sunny, with a high near 91. West wind around 2 mph.
Mostly clear, with a low around 75.
A slight chance of showers and thunderstorms after 1pm. Sunny, with a high near 93. Chance of precipitation is 20%.
A slight chance of showers and thunderstorms before 7pm. Mostly clear, with a low around 67. Chance of precipitation is 20%.
Sunny, with a high near 82.
Partly cloudy, with a low around 62.
Mostly sunny, with a high near 80.
Partly cloudy, with a low around 64.
A slight chance of rain showers between 7am and 1pm. Mostly sunny, with a high near 83. Chance of precipitation is 20%.
A slight chance of rain showers after 1am. Partly cloudy, with a low around 67. Chance of precipitation is 20%.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Today
Jul 18
|
Mostly Sunny then Slight Chance Showers And Thunderstorms
|
91°F |
3 to 9 mph
W
|
|
Tonight
Jul 18
|
Slight Chance Showers And Thunderstorms
|
73°F |
1 to 7 mph
W
|
|
Sunday
Jul 19
|
Mostly Sunny then Chance Showers And Thunderstorms
|
89°F |
2 mph
N
|
|
Sunday Night
Jul 19
|
Chance Showers And Thunderstorms
|
70°F |
2 mph
NE
|
|
Monday
Jul 20
|
Mostly Sunny
|
91°F |
2 mph
W
|
|
Monday Night
Jul 20
|
Mostly Clear
|
75°F |
2 to 6 mph
SW
|
|
Tuesday
Jul 21
|
Sunny then Slight Chance Showers And Thunderstorms
|
93°F |
6 to 12 mph
W
|
|
Tuesday Night
Jul 21
|
Slight Chance Showers And Thunderstorms then Mostly Clear
|
67°F |
6 to 10 mph
N
|
|
Wednesday
Jul 22
|
Sunny
|
82°F |
6 to 10 mph
N
|
|
Wednesday Night
Jul 22
|
Partly Cloudy
|
62°F |
1 to 8 mph
NE
|
|
Thursday
Jul 23
|
Mostly Sunny
|
80°F |
3 mph
E
|
|
Thursday Night
Jul 23
|
Partly Cloudy
|
64°F |
1 to 5 mph
E
|
|
Friday
Jul 24
|
Slight Chance Rain Showers
|
83°F |
2 to 6 mph
SE
|
|
Friday Night
Jul 24
|
Partly Cloudy then Slight Chance Rain Showers
|
67°F |
1 to 6 mph
SE
|
Major City Forecasts
Live forecast snapshots for major cities across Washington County.
Coverage
Forecast coverage currently spans 2 of 2 mapped cities in Washington County.
Largest mapped city population in this region: 2,984.
