St. Johns, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Johns, a village in Perry County, Illinois.
Today
99°F
Sunny
Sunny. High near 99, with temperatures falling to around 97 in the afternoon. West southwest wind 3 to 8 mph.
7-day forecast for St. Johns
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 99°F | Sunny | 3 to 8 mph WSW | 2% |
| Tonight | 72°F | Mostly Clear | 5 mph SSW | 2% |
| Sunday | 97°F | Mostly Sunny | 3 to 7 mph WSW | 2% |
| Sunday Night | 68°F | Mostly Cloudy then Chance Showers And Thunderstorms | 6 mph N | 41% |
| Monday | 84°F | Showers And Thunderstorms Likely | 5 to 10 mph NNE | 61% |
| Monday Night | 60°F | Showers And Thunderstorms Likely then Slight Chance Showers And Thunderstorms | 6 to 10 mph NNE | 61% |
| Tuesday | 75°F | Slight Chance Showers And Thunderstorms | 8 to 13 mph N | 24% |
| Tuesday Night | 55°F | Mostly Cloudy | 5 to 13 mph N | 11% |
| Wednesday | 76°F | Mostly Sunny | 7 to 10 mph N | 2% |
| Wednesday Night | 55°F | Partly Cloudy | 2 to 9 mph N | 0% |
| Thursday | 77°F | Mostly Sunny | 3 to 9 mph N | 2% |
| Thursday Night | 57°F | Partly Cloudy | 2 to 7 mph NNE | 4% |
| Friday | 78°F | Mostly Sunny | 3 to 9 mph NNE | 4% |
| Friday Night | 57°F | Partly Cloudy | 3 to 7 mph NE | 2% |
Forecast source: National Weather Service (api.weather.gov) for St. Johns (38.035, -89.239). Updated through the day.
Growing snapshot for St. Johns
Last spring frost
Apr 6
First fall frost
Oct 22
Growing season
199 days
Hardiness zone
7a
More local growing data for St. Johns: nearby ZIP 62832 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Du Quoin 4 Se, Il (3.6 mi from St. Johns). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.