Petersburg, IL Weather Forecast
Local 7-day forecast
Mostly Sunny then Slight Chance Showers And Thunderstorms
Track current conditions, temperature changes, wind, and the full daily outlook for Petersburg, IL in one place.
A slight chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 93. Heat index values as high as 103. West wind 5 to 10 mph. Chance of precipitation is 20%.
Local Weather Overview
This forecast page for Petersburg, IL is designed for quick trip planning, giving you a clean read on daytime highs, overnight lows, and changing conditions across the upcoming forecast window. Latest sync: Jul 17, 2026 6:31 AM CDT.
The active forecast window currently covers Jul 18 to Jul 23, 2026 for Petersburg, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Jul 18 to Jul 23, 2026
- Latest sync
- Jul 17, 2026 6:31 AM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in Petersburg
Monday looks like the warmest upcoming period in Petersburg at 94 degrees F.
Wednesday Night is the coolest period ahead with temperatures near 65 degrees F.
The strongest winds are forecast for Tuesday at about 6 to 12 mph NW.
Precipitation is mentioned in 4 upcoming forecast periods.
Forecast Details
- Last updated
- Jul 17, 2026 6:31 AM CDT
- Coverage
- 6 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 chance of showers and thunderstorms. Partly cloudy, with a low around 75. West wind 3 to 9 mph. Chance of precipitation is 30%.
A slight chance of rain showers before 7am, then a chance of showers and thunderstorms between 1pm and 4pm, then a chance of showers and thunderstorms. Mostly sunny, with a high near 91. Chance of precipitation is 30%.
A chance of showers and thunderstorms before 7pm. Mostly clear, with a low around 72. Chance of precipitation is 30%.
Mostly sunny, with a high near 94.
Partly cloudy, with a low around 76.
Mostly sunny, with a high near 94.
Partly cloudy, with a low around 70.
Mostly sunny, with a high near 85.
Partly cloudy, with a low around 65.
Mostly sunny, with a high near 85.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Saturday
Jul 18
|
Mostly Sunny then Slight Chance Showers And Thunderstorms
|
93°F |
5 to 10 mph
W
|
|
Saturday Night
Jul 18
|
Chance Showers And Thunderstorms
|
75°F |
3 to 9 mph
W
|
|
Sunday
Jul 19
|
Chance Showers And Thunderstorms
|
91°F |
6 mph
N
|
|
Sunday Night
Jul 19
|
Chance Showers And Thunderstorms then Mostly Clear
|
72°F |
1 to 6 mph
E
|
|
Monday
Jul 20
|
Mostly Sunny
|
94°F |
2 to 6 mph
S
|
|
Monday Night
Jul 20
|
Partly Cloudy
|
76°F |
6 mph
SW
|
|
Tuesday
Jul 21
|
Mostly Sunny
|
94°F |
6 to 12 mph
NW
|
|
Tuesday Night
Jul 21
|
Partly Cloudy
|
70°F |
7 to 12 mph
N
|
|
Wednesday
Jul 22
|
Mostly Sunny
|
85°F |
7 to 10 mph
NE
|
|
Wednesday Night
Jul 22
|
Partly Cloudy
|
65°F |
3 to 9 mph
NE
|
|
Thursday
Jul 23
|
Mostly Sunny
|
85°F |
3 to 8 mph
E
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Petersburg.
