Petersburg, IL Weather & Growing Conditions
Overnight
55°F
Mostly Cloudy
Mostly cloudy, with a low around 55. Southwest wind around 12 mph, with gusts as high as 22 mph. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 55°F | Mostly Cloudy | 12 mph SW | 11% |
| Wednesday | 59°F | Slight Chance Drizzle | 12 to 15 mph WSW | 10% |
| Wednesday Night | 42°F | Slight Chance Drizzle then Mostly Cloudy | 12 mph WSW | 10% |
| Thursday | 59°F | Mostly Cloudy | 10 to 14 mph W | 14% |
| Thursday Night | 42°F | Mostly Cloudy | 5 to 8 mph NW | 14% |
| Friday | 54°F | Partly Sunny | 10 mph N | 4% |
| Friday Night | 32°F | Partly Cloudy | 1 to 7 mph NNW | 0% |
| Saturday | 53°F | Sunny | 1 to 5 mph NNW | 0% |
| Saturday Night | 32°F | Mostly Clear | 2 mph WNW | 1% |
| Sunday | 58°F | Sunny | 2 to 7 mph W | 1% |
| Sunday Night | 33°F | Clear | 3 mph WSW | 1% |
| Monday | 64°F | Sunny | 2 to 7 mph SW | 0% |
| Monday Night | 38°F | Clear | 5 mph SW | 0% |
| Tuesday | 66°F | Sunny | 5 mph WNW | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Petersburg, IL
Last spring frost
Apr 13
First fall frost
Oct 21
Growing season
189 days
Hardiness zone
6a
Explore more for Petersburg, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Petersburg 1E, Il (1.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.