Forreston, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Forreston, a village in Ogle County, Illinois.
Tonight
63°F
Slight Chance Rain Showers then Showers And Thunderstorms Likely
A slight chance of rain showers between 11pm and midnight, then showers and thunderstorms likely. Some of the storms could produce heavy rain. Mostly cloudy, with a low around 63. East southeast wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 60%. New rainfall amounts between three quarters and one inch possible.
7-day forecast for Forreston
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 63°F | Slight Chance Rain Showers then Showers And Thunderstorms Likely | 10 to 15 mph ESE | 62% |
| Saturday | 78°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 10 mph SE | 91% |
| Saturday Night | 62°F | Showers And Thunderstorms Likely | 5 to 10 mph N | 74% |
| Sunday | 67°F | Showers And Thunderstorms Likely | 10 to 20 mph NE | 74% |
| Sunday Night | 54°F | Chance Rain Showers | 15 to 20 mph ENE | 54% |
| Monday | 64°F | Chance Rain Showers | 15 to 20 mph ENE | 44% |
| Monday Night | 49°F | Chance Rain Showers | 10 to 20 mph NE | 43% |
| Tuesday | 62°F | Chance Rain Showers | 15 mph NE | 27% |
| Tuesday Night | 47°F | Mostly Cloudy | 5 to 15 mph NE | 8% |
| Wednesday | 66°F | Mostly Sunny | 5 to 10 mph NE | 4% |
| Wednesday Night | 49°F | Partly Cloudy | 5 to 10 mph NE | 2% |
| Thursday | 67°F | Mostly Sunny | 5 mph NNE | 5% |
| Thursday Night | 51°F | Partly Cloudy | 0 to 5 mph NE | 6% |
| Friday | 69°F | Mostly Sunny | 0 to 5 mph NE | 6% |
Forecast source: National Weather Service (api.weather.gov) for Forreston (42.127, -89.578). Updated through the day.
Growing snapshot for Forreston
Last spring frost
Apr 29
First fall frost
Oct 7
Growing season
161 days
Hardiness zone
5b
More local growing data for Forreston: nearby ZIP 61030 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Baileyville
Byron
Creston
Davis Junction
Hillcrest
Holcomb
Kings
Leaf River
Monroe Center
Mount Morris
Oregon
Polo
Rochelle
Stillman Valley
Climate data from the nearest NOAA station, Polo 5Nw, Il (5.9 mi from Forreston). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.