St. Jacob, IL Weather & Growing Conditions
Today
96°F
Partly Sunny
Partly sunny, with a high near 96. Heat index values as high as 100. Southwest wind around 7 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 96°F | Partly Sunny | 7 mph SW | 6% |
| Tonight | 72°F | Partly Cloudy | 5 mph S | 3% |
| Sunday | 92°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 2 to 7 mph W | 23% |
| Sunday Night | 66°F | Showers And Thunderstorms Likely | 6 to 10 mph NE | 56% |
| Monday | 79°F | Showers And Thunderstorms Likely | 7 to 13 mph NE | 66% |
| Monday Night | 59°F | Showers And Thunderstorms Likely | 7 to 13 mph NE | 59% |
| Tuesday | 71°F | Slight Chance Rain Showers then Partly Sunny | 13 mph NE | 19% |
| Tuesday Night | 54°F | Mostly Cloudy | 6 to 13 mph N | 8% |
| Wednesday | 74°F | Mostly Sunny | 7 to 10 mph N | 3% |
| Wednesday Night | 55°F | Partly Cloudy | 2 to 9 mph N | 0% |
| Thursday | 76°F | Mostly Sunny | 3 to 9 mph N | 1% |
| Thursday Night | 57°F | Partly Cloudy | 2 to 8 mph NE | 3% |
| Friday | 78°F | Mostly Sunny | 3 to 8 mph NE | 5% |
| Friday Night | 57°F | Partly Cloudy | 3 to 7 mph NE | 5% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for St. Jacob, IL
Last spring frost
Apr 12
First fall frost
Oct 20
Growing season
189 days
Hardiness zone
7a
Explore more for St. Jacob, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Belleville Siu Rsch, Il (13.4 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.