Harmon, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harmon, a village in Lee County, Illinois.
Today
85°F
Mostly Sunny
Mostly sunny, with a high near 85. South southwest wind 5 to 10 mph.
7-day forecast for Harmon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 85°F | Mostly Sunny | 5 to 10 mph SSW | 3% |
| Tonight | 67°F | Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms | 0 to 5 mph S | 69% |
| Wednesday | 77°F | Showers And Thunderstorms Likely | 0 to 5 mph W | 74% |
| Wednesday Night | 62°F | Showers And Thunderstorms | 0 to 5 mph NNE | 82% |
| Thursday | 79°F | Chance Rain Showers | 0 to 5 mph NE | 48% |
| Thursday Night | 61°F | Mostly Clear | 0 mph | 14% |
| Friday | 82°F | Mostly Sunny | 0 to 5 mph SSE | 6% |
| Friday Night | 64°F | Mostly Clear | 0 mph | 8% |
| Saturday | 85°F | Sunny | 5 to 10 mph SSW | 9% |
| Saturday Night | 69°F | Mostly Clear then Slight Chance Showers And Thunderstorms | 5 to 10 mph S | 18% |
| Sunday | 87°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 10 to 15 mph SSW | 18% |
| Sunday Night | 70°F | Chance Showers And Thunderstorms | 5 to 10 mph S | 35% |
| Monday | 86°F | Chance Showers And Thunderstorms | 5 to 10 mph S | 35% |
| Monday Night | 70°F | Chance Showers And Thunderstorms | 5 to 10 mph W | 40% |
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 Aug 4, 2026.