Harmon, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harmon, a village in Lee County, Illinois.
This Afternoon
68°F
Rain Showers
Rain showers. Mostly cloudy. High near 68, with temperatures falling to around 66 in the afternoon. South southeast wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Harmon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 68°F | Rain Showers | 15 mph SSE | 85% |
| Tonight | 55°F | Rain Showers | 10 to 15 mph SSE | 82% |
| Wednesday | 58°F | Chance Rain Showers then Mostly Cloudy | 15 mph SSW | 28% |
| Wednesday Night | 46°F | Slight Chance Rain Showers | 15 mph SW | 24% |
| Thursday | 55°F | Chance Rain Showers | 10 to 15 mph WSW | 50% |
| Thursday Night | 41°F | Chance Rain Showers | 5 to 10 mph NW | 30% |
| Friday | 52°F | Slight Chance Rain Showers then Partly Sunny | 5 to 10 mph N | 16% |
| Friday Night | 33°F | Partly Cloudy | 0 to 5 mph NNW | 1% |
| Saturday | 52°F | Mostly Sunny | 0 to 5 mph WNW | 3% |
| Saturday Night | 34°F | Partly Cloudy | 0 mph | 4% |
| Sunday | 58°F | Mostly Sunny | 5 to 10 mph W | 12% |
| Sunday Night | 34°F | Mostly Clear | 0 to 5 mph W | 4% |
| Monday | 62°F | Sunny | 5 to 10 mph SW | 2% |
| Monday Night | 39°F | Mostly Clear | 5 mph W | 0% |
Forecast source: National Weather Service (api.weather.gov) for Harmon (41.723, -89.554). Updated through the day.
Growing snapshot for Harmon
Last spring frost
Apr 24
First fall frost
Oct 14
Growing season
172 days
Hardiness zone
5b
More local growing data for Harmon: nearby ZIP 61042 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Amboy
Ashton
Compton
Dixon
Franklin Grove
Grand Detour
Lee
Lee Center
Lost Nation
Nachusa
Nelson
Paw Paw
Steward
Sublette
West Brooklyn
Climate data from the nearest NOAA station, Walnut, Il (9.5 mi from Harmon). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.