Marengo, IL Weather & Growing Conditions
Tonight
61°F
Slight Chance Rain Showers then Showers And Thunderstorms Likely
A slight chance of rain showers before 8pm, then showers and thunderstorms likely. Some of the storms could produce heavy rain. Mostly cloudy, with a low around 61. East wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 70%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 61°F | Slight Chance Rain Showers then Showers And Thunderstorms Likely | 10 mph E | 65% |
| Saturday | 76°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 10 mph ESE | 93% |
| Saturday Night | 62°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 5 to 10 mph ENE | 78% |
| Sunday | 67°F | Showers And Thunderstorms Likely | 10 to 15 mph NE | 72% |
| Sunday Night | 54°F | Chance Rain Showers | 10 to 15 mph NE | 48% |
| Monday | 64°F | Chance Rain Showers | 15 mph ENE | 39% |
| Monday Night | 50°F | Chance Rain Showers | 10 to 15 mph NE | 39% |
| Tuesday | 62°F | Slight Chance Rain Showers | 10 to 15 mph NE | 20% |
| Tuesday Night | 48°F | Mostly Cloudy | 5 to 10 mph NE | 12% |
| Wednesday | 65°F | Partly Sunny | 5 to 10 mph NE | 6% |
| Wednesday Night | 50°F | Mostly Cloudy | 0 to 5 mph NNE | 4% |
| Thursday | 68°F | Partly Sunny | 0 to 5 mph NNE | 4% |
| Thursday Night | 50°F | Mostly Cloudy | 0 to 5 mph NNE | 4% |
| Friday | 70°F | Mostly Sunny | 0 to 5 mph NNE | 5% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Marengo, IL
Last spring frost
Apr 28
First fall frost
Oct 12
Growing season
166 days
Hardiness zone
5b
Explore more for Marengo, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Marengo, Il (2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.