Princeton, IL Weather & Growing Conditions
Today
86°F
Mostly Sunny
Mostly sunny, with a high near 86. Southwest wind 5 to 10 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 86°F | Mostly Sunny | 5 to 10 mph SW | 1% |
| Tonight | 67°F | Chance Showers And Thunderstorms | 5 mph S | 47% |
| Wednesday | 80°F | Showers And Thunderstorms Likely | 5 mph SW | 61% |
| Wednesday Night | 64°F | Showers And Thunderstorms | 0 to 5 mph NE | 86% |
| Thursday | 78°F | Chance Showers And Thunderstorms | 5 mph NE | 58% |
| Thursday Night | 62°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 mph | 23% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph SE | 9% |
| Friday Night | 64°F | Mostly Clear | 0 mph | 9% |
| Saturday | 84°F | Mostly Sunny | 5 mph SW | 8% |
| Saturday Night | 69°F | Mostly Clear then Slight Chance Showers And Thunderstorms | 5 to 10 mph S | 15% |
| Sunday | 86°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 10 to 15 mph SW | 15% |
| Sunday Night | 70°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph S | 33% |
| Monday | 86°F | Chance Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 5 to 10 mph S | 33% |
| Monday Night | 70°F | Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms | 10 mph SW | 37% |
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 Aug 4, 2026.