Somonauk, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Somonauk, a village in Dekalb County, Illinois.
This Afternoon
74°F
Chance Rain Showers
A chance of rain showers. Partly sunny, with a high near 74. East wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Somonauk
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 74°F | Chance Rain Showers | 10 mph E | 28% |
| Tonight | 64°F | Slight Chance Rain Showers then Chance Showers And Thunderstorms | 10 mph E | 38% |
| Saturday | 80°F | Showers And Thunderstorms Likely | 5 to 10 mph SE | 78% |
| Saturday Night | 65°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 5 to 10 mph NNW | 80% |
| Sunday | 70°F | Showers And Thunderstorms | 10 to 15 mph NE | 80% |
| Sunday Night | 56°F | Showers And Thunderstorms Likely | 15 mph NE | 68% |
| Monday | 66°F | Chance Rain Showers | 15 mph ENE | 54% |
| Monday Night | 52°F | Chance Rain Showers | 15 mph NE | 32% |
| Tuesday | 64°F | Slight Chance Rain Showers | 15 mph NE | 24% |
| Tuesday Night | 51°F | Mostly Cloudy | 10 to 15 mph NNE | 10% |
| Wednesday | 68°F | Partly Sunny | 10 to 15 mph NNE | 6% |
| Wednesday Night | 51°F | Partly Cloudy | 5 to 10 mph NNE | 4% |
| Thursday | 69°F | Partly Sunny | 5 to 10 mph NNE | 3% |
| Thursday Night | 53°F | Partly Cloudy | 5 mph NNE | 3% |
Forecast source: National Weather Service (api.weather.gov) for Somonauk (41.635, -88.687). Updated through the day.
Growing snapshot for Somonauk
Last spring frost
Apr 28
First fall frost
Oct 13
Growing season
166 days
Hardiness zone
5b
More local growing data for Somonauk: nearby ZIP 60552 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Cortland
DeKalb
Genoa
Hinckley
Kingston
Kirkland
Lake Holiday
Malta
Sandwich
Shabbona
Sycamore
Waterman
Climate data from the nearest NOAA station, Chicago Aurora Muni Ap, Il (13.6 mi from Somonauk). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.