Marietta, IL Weather Forecast
Local 7-day forecast
Mostly Cloudy
Track current conditions, temperature changes, wind, and the full daily outlook for Marietta, IL in one place.
Mostly cloudy, with a low around 73. Southwest wind around 6 mph, with gusts as high as 16 mph. New rainfall amounts less than a tenth of an inch possible.
Local Weather Overview
This forecast page for Marietta, 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: Aug 12, 2026 5:21 AM CDT.
The active forecast window currently covers Aug 12 to Aug 18, 2026 for Marietta, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Aug 12 to Aug 18, 2026
- Latest sync
- Aug 12, 2026 5:21 AM CDT
- Forecast office
- ILX
- Source
- NOAA / NWS
Daily Outlook
This Week in Marietta
Saturday looks like the warmest upcoming period in Marietta at 89 degrees F.
Monday Night is the coolest period ahead with temperatures near 63 degrees F.
The strongest winds are forecast for Wednesday at about 8 mph S.
Precipitation is mentioned in 14 upcoming forecast periods.
Forecast Details
- Last updated
- Aug 12, 2026 5:21 AM CDT
- Coverage
- 7 days
- Time zone
- America/Chicago
- Forecast office
- ILX
- Radar station
- KILX
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 before 10am, then showers and thunderstorms likely between 10am and noon, then a chance of showers and thunderstorms between noon and 5pm. Partly sunny, with a high near 86. South wind around 8 mph, with gusts as high as 23 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.
A chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 70. East southeast wind 3 to 7 mph. Chance of precipitation is 30%. New rainfall amounts between a quarter and half of an inch possible.
A chance of showers and thunderstorms before 10am, then a chance of showers and thunderstorms between 10am and 4pm, then a chance of showers and thunderstorms. Mostly cloudy, with a high near 85. East southeast wind 5 to 8 mph. Chance of precipitation is 50%. New rainfall amounts between a quarter and half of an inch possible.
A chance of showers and thunderstorms before 7pm, then showers and thunderstorms likely. Mostly cloudy, with a low around 69. East northeast wind 3 to 7 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.
Showers and thunderstorms likely before 7am, then a slight chance of showers and thunderstorms between 7am and 1pm. Mostly cloudy, with a high near 86. East wind around 5 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch possible.
A chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 72. East southeast wind 5 to 8 mph, with gusts as high as 18 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
A chance of showers and thunderstorms before 1pm. Mostly sunny, with a high near 89. Chance of precipitation is 30%.
A slight chance of showers and thunderstorms after 1am. Mostly clear, with a low around 72.
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 85.
A slight chance of showers and thunderstorms. Partly cloudy, with a low around 67.
A slight chance of rain showers before 7am. Mostly sunny, with a high near 80.
A slight chance of rain showers after 1am. Partly cloudy, with a low around 63.
A slight chance of rain showers before 7am. Mostly sunny, with a high near 81.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Overnight
Aug 12
|
Mostly Cloudy
|
73°F |
6 mph
SW
|
|
Wednesday
Aug 12
|
Chance Showers And Thunderstorms
|
86°F |
8 mph
S
|
|
Wednesday Night
Aug 12
|
Partly Cloudy then Chance Showers And Thunderstorms
|
70°F |
3 to 7 mph
ESE
|
|
Thursday
Aug 13
|
Chance Showers And Thunderstorms
|
85°F |
5 to 8 mph
ESE
|
|
Thursday Night
Aug 13
|
Chance Showers And Thunderstorms then Showers And Thunderstorms Likely
|
69°F |
3 to 7 mph
ENE
|
|
Friday
Aug 14
|
Showers And Thunderstorms Likely then Slight Chance Showers And Thunderstorms
|
86°F |
5 mph
E
|
|
Friday Night
Aug 14
|
Partly Cloudy then Chance Showers And Thunderstorms
|
72°F |
5 to 8 mph
ESE
|
|
Saturday
Aug 15
|
Chance Showers And Thunderstorms
|
89°F |
6 mph
S
|
|
Saturday Night
Aug 15
|
Mostly Clear then Slight Chance Showers And Thunderstorms
|
72°F |
5 mph
SW
|
|
Sunday
Aug 16
|
Slight Chance Showers And Thunderstorms
|
85°F |
6 mph
WNW
|
|
Sunday Night
Aug 16
|
Slight Chance Showers And Thunderstorms
|
67°F |
1 to 5 mph
N
|
|
Monday
Aug 17
|
Slight Chance Rain Showers then Mostly Sunny
|
80°F |
2 mph
NNE
|
|
Monday Night
Aug 17
|
Partly Cloudy then Slight Chance Rain Showers
|
63°F |
1 mph
N
|
|
Tuesday
Aug 18
|
Slight Chance Rain Showers then Mostly Sunny
|
81°F |
0 mph
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Marietta.