Harmon, IL Weather & Growing Conditions
Today
85°F
Mostly Sunny
Mostly sunny, with a high near 85. South southwest wind 5 to 10 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 85°F | Mostly Sunny | 5 to 10 mph SSW | 3% |
| Tonight | 67°F | Chance Showers And Thunderstorms | 0 to 10 mph S | 65% |
| Wednesday | 78°F | Showers And Thunderstorms Likely | 0 to 5 mph WSW | 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 | 50% |
| Thursday Night | 61°F | Mostly Clear | 0 mph | 14% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph SSE | 6% |
| Friday Night | 64°F | Mostly Clear | 0 mph | 8% |
| Saturday | 84°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 | 86°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 WSW | 40% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Harmon, IL
Last spring frost
Apr 24
First fall frost
Oct 14
Growing season
172 days
Hardiness zone
5b
Explore more for Harmon, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Walnut, Il (9.5 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.