Swansea, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Swansea, a village in St. Clair County, Illinois.
Today
88°F
Sunny
Sunny, with a high near 88. Southeast wind around 3 mph.
7-day forecast for Swansea
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 88°F | Sunny | 3 mph SE | 0% |
| Tonight | 67°F | Mostly Clear | 5 mph SE | 0% |
| Wednesday | 90°F | Sunny | 2 to 6 mph S | 6% |
| Wednesday Night | 72°F | Slight Chance Showers And Thunderstorms | 7 mph S | 61% |
| Thursday | 88°F | Showers And Thunderstorms Likely | 6 mph S | 70% |
| Thursday Night | 71°F | Chance Showers And Thunderstorms | 3 mph SE | 45% |
| Friday | 88°F | Chance Showers And Thunderstorms | 5 mph SW | 45% |
| Friday Night | 70°F | Chance Showers And Thunderstorms | 3 mph SW | 36% |
| Saturday | 89°F | Chance Showers And Thunderstorms then Mostly Sunny | 5 mph S | 36% |
| Saturday Night | 72°F | Partly Cloudy | 6 mph S | 8% |
| Sunday | 92°F | Sunny | 5 to 8 mph S | 7% |
| Sunday Night | 74°F | Mostly Clear | 6 to 9 mph S | 5% |
| Monday | 94°F | Sunny | 8 mph SW | 5% |
| Monday Night | 75°F | Slight Chance Showers And Thunderstorms | 9 mph SW | 15% |
Forecast source: National Weather Service (api.weather.gov) for Swansea (38.552, -89.988). Updated through the day.
Growing snapshot for Swansea
Last spring frost
Apr 12
First fall frost
Oct 20
Growing season
189 days
Hardiness zone
7a
More local growing data for Swansea: nearby ZIP 62226 weather · frost dates · planting calendar · Illinois frost dates
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Climate data from the nearest NOAA station, Belleville Siu Rsch, Il (8.4 mi from Swansea). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.