Petersburg, IL Weather & Growing Conditions
Tonight
72°F
Partly Cloudy
Partly cloudy, with a low around 72. East southeast wind around 8 mph, with gusts as high as 16 mph. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 72°F | Partly Cloudy | 8 mph ESE | 5% |
| Saturday | 92°F | Partly Sunny | 8 mph SW | 11% |
| Saturday Night | 69°F | Mostly Cloudy then Chance Showers And Thunderstorms | 7 mph SSW | 36% |
| Sunday | 83°F | Rain Showers Likely | 3 to 10 mph NNW | 62% |
| Sunday Night | 60°F | Showers And Thunderstorms Likely | 8 to 12 mph NE | 69% |
| Monday | 70°F | Showers And Thunderstorms Likely | 12 mph NE | 69% |
| Monday Night | 55°F | Chance Showers And Thunderstorms | 8 to 12 mph NE | 47% |
| Tuesday | 67°F | Chance Rain Showers then Mostly Cloudy | 10 mph NE | 32% |
| Tuesday Night | 51°F | Mostly Cloudy | 5 to 9 mph NNE | 4% |
| Wednesday | 71°F | Partly Sunny | 8 mph NNE | 3% |
| Wednesday Night | 53°F | Partly Cloudy | 2 to 7 mph NNE | 0% |
| Thursday | 72°F | Mostly Sunny | 3 to 7 mph NNE | 3% |
| Thursday Night | 55°F | Partly Cloudy | 2 to 6 mph NNE | 4% |
| Friday | 74°F | Mostly Sunny | 3 to 7 mph NNE | 4% |
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 Sep 19, 2026.