Princeton, IL Weather & Growing Conditions
Tonight
65°F
Mostly Cloudy then Chance Showers And Thunderstorms
A chance of showers and thunderstorms after 1am. Mostly cloudy. Low around 65, with temperatures rising to around 67 overnight. East wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 40%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 65°F | Mostly Cloudy then Chance Showers And Thunderstorms | 10 mph E | 35% |
| Saturday | 82°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 10 mph SE | 64% |
| Saturday Night | 65°F | Showers And Thunderstorms | 5 mph N | 81% |
| Sunday | 72°F | Rain Showers | 10 to 15 mph NE | 81% |
| Sunday Night | 57°F | Showers And Thunderstorms | 15 mph NE | 76% |
| Monday | 65°F | Showers And Thunderstorms Likely | 15 mph NE | 62% |
| Monday Night | 52°F | Chance Rain Showers | 10 to 20 mph NE | 43% |
| Tuesday | 64°F | Chance Rain Showers | 15 mph NE | 38% |
| Tuesday Night | 50°F | Mostly Cloudy | 5 to 15 mph NE | 5% |
| Wednesday | 68°F | Partly Sunny | 10 mph NE | 5% |
| Wednesday Night | 52°F | Partly Cloudy | 5 to 10 mph NE | 5% |
| Thursday | 70°F | Mostly Sunny | 5 mph N | 4% |
| Thursday Night | 53°F | Partly Cloudy | 0 to 5 mph NE | 5% |
| Friday | 72°F | Mostly Sunny | 5 mph NE | 5% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Princeton, IL
Last spring frost
Apr 22
First fall frost
Oct 17
Growing season
177 days
Hardiness zone
5b
Explore more for Princeton, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Princeton, Il (1.7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.