Harmon, IL Weather & Growing Conditions
Tonight
65°F
Mostly Cloudy then Chance Showers And Thunderstorms
A chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 65. East southeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 40%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 65°F | Mostly Cloudy then Chance Showers And Thunderstorms | 10 mph ESE | 39% |
| Saturday | 81°F | Showers And Thunderstorms Likely | 5 to 10 mph SSE | 74% |
| Saturday Night | 64°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 5 to 10 mph N | 79% |
| Sunday | 70°F | Showers And Thunderstorms | 10 to 15 mph NE | 78% |
| Sunday Night | 56°F | Showers And Thunderstorms Likely | 15 mph NE | 64% |
| Monday | 66°F | Rain Showers Likely | 15 mph ENE | 55% |
| Monday Night | 51°F | Chance Rain Showers | 10 to 15 mph NE | 39% |
| Tuesday | 64°F | Chance Rain Showers | 10 to 15 mph NE | 34% |
| Tuesday Night | 49°F | Mostly Cloudy | 5 to 10 mph NE | 6% |
| Wednesday | 68°F | Partly Sunny | 5 to 10 mph NNE | 4% |
| Wednesday Night | 50°F | Partly Cloudy | 0 to 5 mph NE | 4% |
| Thursday | 70°F | Mostly Sunny | 0 to 5 mph NNE | 4% |
| Thursday Night | 52°F | Partly Cloudy | 0 to 5 mph NE | 5% |
| Friday | 72°F | Mostly Sunny | 0 to 5 mph NNE | 5% |
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 Sep 19, 2026.