Swansea, IL Weather & Growing Conditions
This Afternoon
98°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Sunny, with a high near 98. Heat index values as high as 104. South wind around 5 mph. Chance of precipitation is 30%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 98°F | Chance Showers And Thunderstorms | 5 mph S | 26% |
| Tonight | 73°F | Slight Chance Showers And Thunderstorms then Mostly Clear | 5 mph SE | 24% |
| Saturday | 98°F | Mostly Sunny | 3 to 8 mph SW | 6% |
| Saturday Night | 74°F | Partly Cloudy | 5 mph S | 1% |
| Sunday | 95°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 3 to 7 mph W | 17% |
| Sunday Night | 68°F | Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms | 8 mph N | 54% |
| Monday | 82°F | Showers And Thunderstorms Likely | 6 to 10 mph N | 67% |
| Monday Night | 62°F | Showers And Thunderstorms Likely | 7 to 12 mph N | 67% |
| Tuesday | 72°F | Chance Rain Showers then Mostly Cloudy | 12 mph N | 27% |
| Tuesday Night | 55°F | Mostly Cloudy | 6 to 12 mph N | 6% |
| Wednesday | 75°F | Mostly Sunny | 9 mph N | 3% |
| Wednesday Night | 56°F | Partly Cloudy | 3 to 8 mph N | 2% |
| Thursday | 77°F | Mostly Sunny | 3 to 8 mph N | 2% |
| Thursday Night | 58°F | Partly Cloudy | 3 to 7 mph N | 2% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Swansea, IL
Last spring frost
Apr 12
First fall frost
Oct 20
Growing season
189 days
Hardiness zone
7a
Explore more for Swansea, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Belleville Siu Rsch, Il (8.4 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.