St. Jacob, IL Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for St. Jacob, a village in Madison County, Illinois.

Overnight

65°F

Clear

Clear, with a low around 65. East wind around 1 mph.

7-day forecast for St. Jacob

When	Temp	Forecast	Wind	Precip
Overnight	65°F	Clear	1 mph E	0%
Tuesday	87°F	Sunny	0 to 3 mph SE	0%
Tuesday Night	67°F	Mostly Clear	3 mph SE	0%
Wednesday	90°F	Sunny	1 to 5 mph S	7%
Wednesday Night	71°F	Slight Chance Showers And Thunderstorms	6 mph S	65%
Thursday	86°F	Showers And Thunderstorms Likely	6 mph S	74%
Thursday Night	70°F	Chance Showers And Thunderstorms	3 mph SE	43%
Friday	86°F	Chance Showers And Thunderstorms	3 mph SW	43%
Friday Night	70°F	Chance Showers And Thunderstorms	2 mph S	35%
Saturday	88°F	Chance Showers And Thunderstorms	1 to 5 mph S	35%
Saturday Night	72°F	Mostly Clear	6 mph S	10%
Sunday	91°F	Sunny	5 to 9 mph S	8%
Sunday Night	73°F	Mostly Clear	8 mph S	5%
Monday	92°F	Mostly Sunny	5 to 9 mph S	5%

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

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 Aug 4, 2026.