Saint Mary, IL Weather Forecast
Local 7-day forecast
Sunny then Chance Showers And Thunderstorms
Track current conditions, temperature changes, wind, and the full daily outlook for Saint Mary, IL in one place.
A chance of showers and thunderstorms after 5pm. Sunny. High near 93, with temperatures falling to around 91 in the afternoon. Heat index values as high as 105. West wind around 10 mph. Chance of precipitation is 40%.
Local Weather Overview
This forecast page for Saint Mary, 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 12:34 PM CDT.
The active forecast window currently covers Jul 18 to Jul 23, 2026 for Saint Mary, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Jul 18 to Jul 23, 2026
- Latest sync
- Jul 17, 2026 12:34 PM CDT
- Forecast office
- DVN
- Source
- NOAA / NWS
Daily Outlook
This Week in Saint Mary
Saturday looks like the warmest upcoming period in Saint Mary 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 5 to 15 mph NW.
Precipitation is mentioned in 6 upcoming forecast periods.
Forecast Details
- Last updated
- Jul 17, 2026 12:34 PM CDT
- Coverage
- 6 days
- Time zone
- America/Chicago
- Forecast office
- DVN
- 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 1am. Mostly clear, with a low around 70. Heat index values as high as 102. North wind 0 to 10 mph. Chance of precipitation is 40%.
Sunny, with a high near 89.
Mostly clear, with a low around 70.
Mostly sunny, with a high near 93.
A slight chance of showers and thunderstorms after 7pm. Mostly clear, with a low around 74.
A slight chance of showers and thunderstorms before 7am. Sunny, with a high near 90.
Mostly clear, with a low around 65.
Sunny, with a high near 82.
Mostly clear, with a low around 62.
A slight chance of rain showers between 7am and 1pm. Sunny, with a high near 83.
A slight chance of rain showers between 7pm and 1am, then a slight chance of showers and thunderstorms. Partly cloudy, with a low around 64.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Saturday
Jul 18
|
Sunny then Chance Showers And Thunderstorms
|
93°F |
10 mph
W
|
|
Saturday Night
Jul 18
|
Chance Showers And Thunderstorms
|
70°F |
0 to 10 mph
N
|
|
Sunday
Jul 19
|
Sunny
|
89°F |
5 mph
E
|
|
Sunday Night
Jul 19
|
Mostly Clear
|
70°F |
5 mph
SE
|
|
Monday
Jul 20
|
Mostly Sunny
|
93°F |
5 to 10 mph
S
|
|
Monday Night
Jul 20
|
Slight Chance Showers And Thunderstorms
|
74°F |
5 to 10 mph
W
|
|
Tuesday
Jul 21
|
Slight Chance Showers And Thunderstorms then Sunny
|
90°F |
5 to 15 mph
NW
|
|
Tuesday Night
Jul 21
|
Mostly Clear
|
65°F |
5 to 15 mph
N
|
|
Wednesday
Jul 22
|
Sunny
|
82°F |
5 to 10 mph
NE
|
|
Wednesday Night
Jul 22
|
Mostly Clear
|
62°F |
0 to 5 mph
E
|
|
Thursday
Jul 23
|
Slight Chance Rain Showers
|
83°F |
0 to 5 mph
SE
|
|
Thursday Night
Jul 23
|
Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms
|
64°F |
0 to 5 mph
SE
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Saint Mary.