St. Peter, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Peter, a village in Fayette County, Illinois.
This Afternoon
75°F
Slight Chance T-storms
A slight chance of thunderstorms and a slight chance of rain after 4pm. Mostly cloudy, with a high near 75. South wind 17 to 21 mph. Chance of precipitation is 20%.
7-day forecast for St. Peter
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 75°F | Slight Chance T-storms | 17 to 21 mph S | 21% |
| Tonight | 55°F | Rain | 10 to 15 mph S | 99% |
| Wednesday | 64°F | Slight Chance Light Rain then Mostly Cloudy | 7 to 14 mph SW | 23% |
| Wednesday Night | 43°F | Partly Cloudy | 5 mph SW | 0% |
| Thursday | 65°F | Sunny | 5 to 12 mph W | 0% |
| Thursday Night | 43°F | Mostly Cloudy | 3 mph NW | 3% |
| Friday | 58°F | Mostly Cloudy | 3 to 10 mph NW | 7% |
| Friday Night | 38°F | Partly Cloudy | 2 to 6 mph N | 1% |
| Saturday | 56°F | Mostly Sunny | 5 mph NW | 0% |
| Saturday Night | 34°F | Partly Cloudy | 1 mph NW | 1% |
| Sunday | 60°F | Sunny | 1 to 7 mph W | 7% |
| Sunday Night | 34°F | Mostly Clear | 3 mph NW | 5% |
| Monday | 64°F | Sunny | 1 to 8 mph W | 2% |
| Monday Night | 38°F | Mostly Clear | 3 mph SW | 1% |
Forecast source: National Weather Service (api.weather.gov) for St. Peter (38.868, -88.850). Updated through the day.
Growing snapshot for St. Peter
Last spring frost
Apr 3
First fall frost
Oct 24
Growing season
202 days
Hardiness zone
6b
More local growing data for St. Peter: nearby ZIP 62880 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Brownstown 4 Sw, Il (7.2 mi from St. Peter). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.