Grand Detour, IL Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Grand Detour, a community in Lee County, Illinois.

Overnight

55°F

Chance Rain Showers

A chance of rain showers. Cloudy. Low around 55, with temperatures rising to around 59 overnight. South southwest wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.

7-day forecast for Grand Detour

When	Temp	Forecast	Wind	Precip
Overnight	55°F	Chance Rain Showers	15 mph SSW	25%
Wednesday	59°F	Patchy Drizzle	10 to 15 mph SW	17%
Wednesday Night	45°F	Patchy Drizzle	10 to 15 mph WSW	21%
Thursday	55°F	Chance Rain Showers	10 to 15 mph W	35%
Thursday Night	38°F	Slight Chance Rain Showers then Mostly Cloudy	10 mph NNW	21%
Friday	49°F	Partly Sunny	5 to 10 mph N	5%
Friday Night	30°F	Partly Cloudy	0 to 5 mph SSE	0%
Saturday	51°F	Sunny	0 to 5 mph NW	0%
Saturday Night	31°F	Mostly Clear	0 mph	1%
Sunday	56°F	Sunny	0 to 10 mph W	4%
Sunday Night	33°F	Mostly Clear	0 to 5 mph WSW	0%
Monday	61°F	Sunny	0 to 10 mph SW	0%
Monday Night	38°F	Mostly Clear	0 to 5 mph WSW	0%
Tuesday	62°F	Sunny	0 to 5 mph WNW	0%

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

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

All Illinois locations ›

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 Nov 4, 2026.