Marengo, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Marengo, a city in Mchenry County, Illinois.
Overnight
61°F
Mostly Clear
Mostly clear. Low around 61, with temperatures rising to around 63 overnight. South wind around 5 mph.
7-day forecast for Marengo
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 61°F | Mostly Clear | 5 mph S | 0% |
| Tuesday | 84°F | Mostly Sunny | 5 to 10 mph SSW | 1% |
| Tuesday Night | 66°F | Chance Showers And Thunderstorms | 0 to 5 mph SW | 65% |
| Wednesday | 77°F | Showers And Thunderstorms Likely | 0 to 5 mph W | 74% |
| Wednesday Night | 61°F | Showers And Thunderstorms | 0 to 5 mph NW | 77% |
| Thursday | 79°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 0 to 5 mph NE | 47% |
| Thursday Night | 59°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 mph | 15% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph SE | 5% |
| Friday Night | 62°F | Partly Cloudy | 0 to 5 mph S | 8% |
| Saturday | 83°F | Mostly Sunny | 0 to 10 mph SSW | 11% |
| Saturday Night | 68°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SSW | 21% |
| Sunday | 85°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 21% |
| Sunday Night | 68°F | Chance Showers And Thunderstorms | 5 to 10 mph SSW | 43% |
| Monday | 84°F | Chance Rain Showers | 5 mph SSW | 43% |
Forecast source: National Weather Service (api.weather.gov) for Marengo (42.247, -88.598). Updated through the day.
Growing snapshot for Marengo
Last spring frost
Apr 28
First fall frost
Oct 12
Growing season
166 days
Hardiness zone
5b
More local growing data for Marengo: nearby ZIP 60152 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
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Climate data from the nearest NOAA station, Marengo, Il (2 mi from Marengo). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.