Colchester, IL Weather & Growing Conditions
Today
89°F
Sunny
Sunny. High near 89, with temperatures falling to around 87 in the afternoon. South wind around 5 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 89°F | Sunny | 5 mph S | 0% |
| Tonight | 68°F | Slight Chance Showers And Thunderstorms | 0 to 5 mph SE | 20% |
| Wednesday | 83°F | Chance Showers And Thunderstorms | 0 to 5 mph S | 55% |
| Wednesday Night | 65°F | Showers And Thunderstorms | 0 to 5 mph N | 87% |
| Thursday | 81°F | Showers And Thunderstorms | 0 to 5 mph E | 79% |
| Thursday Night | 63°F | Partly Cloudy | 0 mph | 12% |
| Friday | 83°F | Mostly Sunny | 0 mph | 6% |
| Friday Night | 65°F | Slight Chance Showers And Thunderstorms | 0 mph | 21% |
| Saturday | 86°F | Slight Chance Showers And Thunderstorms then Sunny | 0 to 5 mph S | 19% |
| Saturday Night | 70°F | Mostly Clear | 0 to 5 mph S | 8% |
| Sunday | 88°F | Sunny | 5 to 10 mph SW | 7% |
| Sunday Night | 70°F | Mostly Clear then Slight Chance Showers And Thunderstorms | 5 to 10 mph S | 16% |
| Monday | 88°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 5 to 10 mph SW | 16% |
| Monday Night | 71°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph S | 27% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Colchester, IL
Last spring frost
Apr 21
First fall frost
Oct 19
Growing season
180 days
Hardiness zone
6a
Explore more for Colchester, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, La Harpe, Il (13.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.