Harvard, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harvard, a city in Mchenry County, Illinois.
Overnight
58°F
Rain Showers
Rain showers. Cloudy. Low around 58, with temperatures rising to around 60 overnight. South wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Harvard
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 58°F | Rain Showers | 15 mph S | 82% |
| Wednesday | 61°F | Chance Rain Showers | 15 mph SSW | 25% |
| Wednesday Night | 46°F | Mostly Cloudy then Slight Chance Rain Showers | 15 mph SW | 21% |
| Thursday | 54°F | Chance Rain Showers | 10 to 15 mph W | 48% |
| Thursday Night | 39°F | Chance Rain Showers then Mostly Cloudy | 10 mph NNW | 44% |
| Friday | 47°F | Partly Sunny | 10 to 15 mph NNW | 9% |
| Friday Night | 32°F | Partly Cloudy | 0 to 10 mph NNW | 0% |
| Saturday | 50°F | Sunny | 0 to 5 mph NW | 0% |
| Saturday Night | 33°F | Mostly Clear | 0 to 5 mph W | 0% |
| Sunday | 55°F | Sunny | 5 to 10 mph W | 6% |
| Sunday Night | 35°F | Mostly Clear | 0 to 5 mph W | 0% |
| Monday | 59°F | Sunny | 0 to 10 mph WSW | 0% |
| Monday Night | 40°F | Partly Cloudy | 5 mph W | 1% |
| Tuesday | 60°F | Sunny | 5 mph WNW | 0% |
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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Johnsburg
Lake Barrington
Lake in the Hills
Lakemoor
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Marengo
McCullom Lake
McHenry
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Ridgefield
Riley
Ringwood
Solon Mills
Spring Grove
Climate data from the nearest NOAA station, Marengo, Il (11 mi from Harvard). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.