Formosa Junction, IL Weather Forecast
Local 7-day forecast
Isolated Showers And Thunderstorms
Track current conditions, temperature changes, wind, and the full daily outlook for Formosa Junction, IL in one place.
Isolated showers and thunderstorms. Mostly sunny, with a high near 98. Heat index values as high as 105. South wind around 9 mph. Chance of precipitation is 20%.
Local Weather Overview
This forecast page for Formosa Junction, 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 15, 2026 5:16 PM CDT.
The active forecast window currently covers Sep 15 to Sep 21, 2026 for Formosa Junction, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Sep 15 to Sep 21, 2026
- Latest sync
- Sep 15, 2026 5:16 PM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in Formosa Junction
This Afternoon looks like the warmest upcoming period in Formosa Junction at 98 degrees F.
Monday Night is the coolest period ahead with temperatures near 64 degrees F.
The strongest winds are forecast for Saturday at about 6 to 10 mph SW.
Precipitation is mentioned in 9 upcoming forecast periods.
Forecast Details
- Last updated
- Sep 15, 2026 5:16 PM 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
Scattered showers and thunderstorms. Partly cloudy, with a low around 74. Heat index values as high as 102. Southeast wind 2 to 7 mph. Chance of precipitation is 30%.
Scattered showers and thunderstorms. Partly sunny, with a high near 94. Heat index values as high as 103. Southeast wind 2 to 6 mph. Chance of precipitation is 30%.
Isolated showers and thunderstorms before 8pm. Partly cloudy, with a low around 76. Heat index values as high as 101. South wind around 5 mph. Chance of precipitation is 20%.
Sunny, with a high near 97. West wind 3 to 7 mph.
Mostly clear, with a low around 74.
Mostly sunny, with a high near 96.
Mostly clear, with a low around 74.
Mostly sunny, with a high near 97.
A slight chance of rain showers after 1am. Partly cloudy, with a low around 73. Chance of precipitation is 20%.
A slight chance of rain showers before 1pm, then a slight chance of showers and thunderstorms. Mostly sunny, with a high near 92. Chance of precipitation is 20%.
A chance of showers and thunderstorms. Partly cloudy, with a low around 68. Chance of precipitation is 40%.
A chance of showers and thunderstorms. Partly sunny, with a high near 83. Chance of precipitation is 30%.
A chance of rain showers before 1am. Mostly cloudy, with a low around 64. Chance of precipitation is 30%.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
This Afternoon
Sep 15
|
Isolated Showers And Thunderstorms
|
98°F |
9 mph
S
|
|
Tonight
Sep 15
|
Scattered Showers And Thunderstorms
|
74°F |
2 to 7 mph
SE
|
|
Wednesday
Sep 16
|
Scattered Showers And Thunderstorms
|
94°F |
2 to 6 mph
SE
|
|
Wednesday Night
Sep 16
|
Isolated Showers And Thunderstorms then Partly Cloudy
|
76°F |
5 mph
S
|
|
Thursday
Sep 17
|
Sunny
|
97°F |
3 to 7 mph
W
|
|
Thursday Night
Sep 17
|
Mostly Clear
|
74°F |
3 mph
E
|
|
Friday
Sep 18
|
Mostly Sunny
|
96°F |
5 mph
SE
|
|
Friday Night
Sep 18
|
Mostly Clear
|
74°F |
7 mph
S
|
|
Saturday
Sep 19
|
Mostly Sunny
|
97°F |
6 to 10 mph
SW
|
|
Saturday Night
Sep 19
|
Partly Cloudy then Slight Chance Rain Showers
|
73°F |
6 mph
SW
|
|
Sunday
Sep 20
|
Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms
|
92°F |
5 to 10 mph
W
|
|
Sunday Night
Sep 20
|
Chance Showers And Thunderstorms
|
68°F |
6 to 10 mph
N
|
|
Monday
Sep 21
|
Chance Showers And Thunderstorms
|
83°F |
6 to 10 mph
NW
|
|
Monday Night
Sep 21
|
Chance Rain Showers
|
64°F |
6 to 10 mph
N
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Formosa Junction.