Frontenac, IL Weather Forecast
Local 7-day forecast
Showers And Thunderstorms Likely
Track current conditions, temperature changes, wind, and the full daily outlook for Frontenac, IL in one place.
Showers and thunderstorms likely. Mostly cloudy, with a high near 75. Northeast wind 5 to 10 mph. Chance of precipitation is 70%.
Local Weather Overview
This forecast page for Frontenac, 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: Sep 14, 2026 2:45 PM CDT.
The active forecast window currently covers Sep 16 to Sep 20, 2026 for Frontenac, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Sep 16 to Sep 20, 2026
- Latest sync
- Sep 14, 2026 2:45 PM CDT
- Forecast office
- LOT
- Source
- NOAA / NWS
Daily Outlook
This Week in Frontenac
Thursday looks like the warmest upcoming period in Frontenac at 80 degrees F.
Sunday Night is the coolest period ahead with temperatures near 60 degrees F.
The strongest winds are forecast for Sunday at about 10 to 15 mph NE.
Precipitation is mentioned in 10 upcoming forecast periods.
Forecast Details
- Last updated
- Sep 14, 2026 2:45 PM CDT
- Coverage
- 5 days
- Time zone
- America/Chicago
- Forecast office
- LOT
- Radar station
- KLOT
Weather data is provided by the National Weather Service and refreshed automatically for U.S. locations.
Open NOAA sourceExtended Forecast
Showers and thunderstorms likely. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.
Showers and thunderstorms likely before 1pm. Mostly cloudy, with a high near 80.
A slight chance of rain showers after 1am. Mostly cloudy, with a low around 64.
A chance of rain showers. Partly sunny, with a high near 79.
A chance of rain showers. Mostly cloudy, with a low around 65.
Rain showers likely before 1pm, then showers and thunderstorms likely. Partly sunny, with a high near 77.
Showers and thunderstorms likely. Mostly cloudy, with a low around 61.
A chance of showers and thunderstorms. Mostly cloudy, with a high near 74.
A chance of rain showers. Mostly cloudy, with a low around 60.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Wednesday
Sep 16
|
Showers And Thunderstorms Likely
|
75°F |
5 to 10 mph
NE
|
|
Wednesday Night
Sep 16
|
Showers And Thunderstorms Likely
|
66°F |
5 to 10 mph
ESE
|
|
Thursday
Sep 17
|
Showers And Thunderstorms Likely
|
80°F |
5 mph
NNW
|
|
Thursday Night
Sep 17
|
Mostly Cloudy then Slight Chance Rain Showers
|
64°F |
5 mph
NE
|
|
Friday
Sep 18
|
Chance Rain Showers
|
79°F |
5 to 10 mph
E
|
|
Friday Night
Sep 18
|
Chance Rain Showers
|
65°F |
5 to 10 mph
SE
|
|
Saturday
Sep 19
|
Rain Showers Likely
|
77°F |
10 mph
SW
|
|
Saturday Night
Sep 19
|
Showers And Thunderstorms Likely
|
61°F |
10 mph
NNW
|
|
Sunday
Sep 20
|
Chance Showers And Thunderstorms
|
74°F |
10 to 15 mph
NE
|
|
Sunday Night
Sep 20
|
Chance Rain Showers
|
60°F |
5 to 10 mph
E
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Frontenac.