Somonauk, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Somonauk, a village in Dekalb County, Illinois.
This Afternoon
69°F
Rain Showers Likely
Rain showers likely. Mostly cloudy. High near 69, with temperatures falling to around 65 in the afternoon. South southeast wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 70%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Somonauk
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 69°F | Rain Showers Likely | 15 mph SSE | 69% |
| Tonight | 57°F | Rain Showers | 15 mph S | 94% |
| Wednesday | 61°F | Chance Rain Showers | 15 mph SSW | 46% |
| Wednesday Night | 47°F | Mostly Cloudy | 15 mph SW | 14% |
| Thursday | 56°F | Chance Rain Showers | 10 to 15 mph WSW | 43% |
| Thursday Night | 42°F | Chance Rain Showers | 5 to 10 mph WNW | 39% |
| Friday | 52°F | Slight Chance Rain Showers then Mostly Cloudy | 10 mph N | 21% |
| Friday Night | 35°F | Partly Cloudy | 5 to 10 mph NNW | 2% |
| Saturday | 52°F | Mostly Sunny | 5 mph WNW | 4% |
| Saturday Night | 34°F | Partly Cloudy | 0 to 5 mph WSW | 3% |
| Sunday | 57°F | Mostly Sunny | 5 to 10 mph W | 13% |
| Sunday Night | 35°F | Mostly Clear | 5 mph WNW | 6% |
| Monday | 61°F | Sunny | 5 to 10 mph WSW | 3% |
| Monday Night | 39°F | Mostly Clear | 5 to 10 mph W | 1% |
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 Nov 4, 2026.