Harmony, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harmony, a community in Mchenry County, Illinois.
Today
83°F
Mostly Sunny
Mostly sunny, with a high near 83. South southwest wind 5 to 10 mph, with gusts as high as 20 mph.
7-day forecast for Harmony
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 83°F | Mostly Sunny | 5 to 10 mph SSW | 1% |
| Tonight | 66°F | Mostly Cloudy then Slight Chance Showers And Thunderstorms | 0 to 5 mph SW | 60% |
| Wednesday | 77°F | Showers And Thunderstorms Likely | 0 to 5 mph WSW | 74% |
| Wednesday Night | 62°F | Showers And Thunderstorms | 0 to 5 mph NNW | 79% |
| Thursday | 78°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 0 to 5 mph NE | 52% |
| Thursday Night | 60°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 to 5 mph SE | 16% |
| Friday | 80°F | Mostly Sunny | 0 to 5 mph S | 6% |
| Friday Night | 62°F | Mostly Clear | 0 to 5 mph S | 8% |
| Saturday | 82°F | Mostly Sunny | 5 to 10 mph SSW | 11% |
| Saturday Night | 68°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SSW | 20% |
| Sunday | 84°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 20% |
| Sunday Night | 68°F | Chance Showers And Thunderstorms | 5 to 10 mph SSW | 42% |
| Monday | 83°F | Chance Rain Showers | 5 to 10 mph SSW | 42% |
| Monday Night | 68°F | Chance Showers And Thunderstorms | 5 to 10 mph WNW | 45% |
Forecast source: National Weather Service (api.weather.gov) for Harmony (42.159, -88.529). Updated through the day.
Growing snapshot for Harmony
Last spring frost
Apr 28
First fall frost
Oct 12
Growing season
166 days
Hardiness zone
5b
More local growing data for Harmony: nearby ZIP 60180 weather · frost dates · planting calendar · Illinois frost dates
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Climate data from the nearest NOAA station, Marengo, Il (5.3 mi from Harmony). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.