St. Jacob, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Jacob, a village in Madison County, Illinois.
Tonight
55°F
Rain Likely
Rain likely before 4am, then a slight chance of drizzle between 4am and 5am, then a slight chance of rain. Mostly cloudy, with a low around 55. Southwest wind 9 to 14 mph, with gusts as high as 28 mph. Chance of precipitation is 60%.
7-day forecast for St. Jacob
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 55°F | Rain Likely | 9 to 14 mph SW | 63% |
| Wednesday | 63°F | Slight Chance Drizzle then Mostly Cloudy | 8 to 15 mph W | 12% |
| Wednesday Night | 44°F | Partly Cloudy | 6 mph W | 0% |
| Thursday | 64°F | Sunny | 5 to 13 mph W | 1% |
| Thursday Night | 44°F | Mostly Cloudy | 5 mph NW | 5% |
| Friday | 58°F | Partly Sunny | 5 to 12 mph NW | 7% |
| Friday Night | 38°F | Partly Cloudy | 2 to 7 mph N | 1% |
| Saturday | 56°F | Mostly Sunny | 5 mph NW | 0% |
| Saturday Night | 35°F | Partly Cloudy | 1 mph NW | 0% |
| Sunday | 62°F | Sunny | 1 to 8 mph W | 7% |
| Sunday Night | 36°F | Mostly Clear | 1 to 5 mph W | 5% |
| Monday | 66°F | Sunny | 2 to 8 mph SW | 2% |
| Monday Night | 40°F | Mostly Clear | 5 mph SW | 1% |
| Tuesday | 69°F | Sunny | 6 mph W | 0% |
Forecast source: National Weather Service (api.weather.gov) for St. Jacob (38.718, -89.763). Updated through the day.
Growing snapshot for St. Jacob
Last spring frost
Apr 12
First fall frost
Oct 20
Growing season
189 days
Hardiness zone
7a
More local growing data for St. Jacob: nearby ZIP 62281 weather · frost dates · planting calendar · Illinois frost dates
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Climate data from the nearest NOAA station, Belleville Siu Rsch, Il (13.4 mi from St. Jacob). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.