Harvard, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harvard, a city in Mchenry County, Illinois.
Today
83°F
Mostly Sunny
Mostly sunny, with a high near 83. Southwest wind around 10 mph, with gusts as high as 20 mph.
7-day forecast for Harvard
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 83°F | Mostly Sunny | 10 mph SW | 2% |
| Tonight | 65°F | Chance Showers And Thunderstorms | 5 to 10 mph WSW | 74% |
| Wednesday | 76°F | Showers And Thunderstorms Likely | 0 to 5 mph W | 74% |
| Wednesday Night | 60°F | Showers And Thunderstorms Likely | 0 to 5 mph NNE | 69% |
| Thursday | 78°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 0 to 5 mph NE | 38% |
| Thursday Night | 59°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 mph | 15% |
| Friday | 80°F | Mostly Sunny | 0 to 5 mph SSE | 3% |
| Friday Night | 62°F | Mostly Clear | 0 to 5 mph SSW | 6% |
| Saturday | 82°F | Mostly Sunny | 0 to 10 mph SW | 11% |
| Saturday Night | 67°F | Slight Chance Showers And Thunderstorms | 5 mph SSW | 24% |
| Sunday | 84°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 24% |
| Sunday Night | 67°F | Chance Showers And Thunderstorms | 5 to 10 mph SSW | 44% |
| Monday | 83°F | Chance Rain Showers | 5 mph SSW | 44% |
| Monday Night | 66°F | Chance Showers And Thunderstorms | 5 mph WNW | 45% |
Forecast source: National Weather Service (api.weather.gov) for Harvard (42.430, -88.621). Updated through the day.
Growing snapshot for Harvard
Last spring frost
Apr 28
First fall frost
Oct 12
Growing season
166 days
Hardiness zone
5b
More local growing data for Harvard: nearby ZIP 60033 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
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Lake Barrington
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Marengo
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Climate data from the nearest NOAA station, Marengo, Il (11 mi from Harvard). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.