Grand Detour, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Grand Detour, a community in Lee County, Illinois.
This Afternoon
73°F
Showers And Thunderstorms Likely
Showers and thunderstorms likely. Mostly cloudy, with a high near 73. East wind 10 to 15 mph. Chance of precipitation is 70%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Grand Detour
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 73°F | Showers And Thunderstorms Likely | 10 to 15 mph E | 70% |
| Tonight | 63°F | Mostly Cloudy then Chance Showers And Thunderstorms | 5 to 10 mph ESE | 48% |
| Saturday | 79°F | Showers And Thunderstorms Likely | 5 to 10 mph SSE | 85% |
| Saturday Night | 62°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 5 mph NNE | 79% |
| Sunday | 68°F | Showers And Thunderstorms | 10 to 15 mph NE | 77% |
| Sunday Night | 53°F | Rain Showers Likely | 10 to 15 mph NE | 62% |
| Monday | 65°F | Chance Rain Showers | 15 mph ENE | 51% |
| Monday Night | 49°F | Chance Rain Showers | 10 to 15 mph NE | 36% |
| Tuesday | 63°F | Chance Rain Showers | 10 to 15 mph NE | 31% |
| Tuesday Night | 47°F | Mostly Cloudy | 5 to 10 mph NE | 7% |
| Wednesday | 67°F | Partly Sunny | 5 to 10 mph NNE | 3% |
| Wednesday Night | 48°F | Mostly Cloudy | 0 to 5 mph NE | 3% |
| Thursday | 69°F | Mostly Sunny | 0 to 5 mph NNE | 4% |
| Thursday Night | 50°F | Partly Cloudy | 0 to 5 mph NE | 5% |
Forecast source: National Weather Service (api.weather.gov) for Grand Detour (41.901, -89.413). Updated through the day.
Growing snapshot for Grand Detour
Last spring frost
Apr 21
First fall frost
Oct 19
Growing season
180 days
Hardiness zone
5b
More local growing data for Grand Detour: nearby ZIP 61057 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Amboy
Ashton
Compton
Dixon
Franklin Grove
Harmon
Lee
Lee Center
Lost Nation
Nachusa
Nelson
Paw Paw
Steward
Sublette
West Brooklyn
Climate data from the nearest NOAA station, Dixon 1W, Il (6.7 mi from Grand Detour). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.