Sycamore, IL Weather & Growing Conditions
Overnight
63°F
Showers And Thunderstorms Likely
Showers and thunderstorms likely before 5am, then showers and thunderstorms. Cloudy, with a low around 63. East southeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 63°F | Showers And Thunderstorms Likely | 10 mph ESE | 83% |
| Saturday | 77°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 10 mph SE | 100% |
| Saturday Night | 62°F | Showers And Thunderstorms | 5 to 10 mph E | 95% |
| Sunday | 69°F | Showers And Thunderstorms Likely | 10 to 15 mph NE | 58% |
| Sunday Night | 55°F | Chance Rain Showers | 15 mph NE | 27% |
| Monday | 64°F | Chance Rain Showers | 15 mph ENE | 42% |
| Monday Night | 50°F | Slight Chance Rain Showers then Mostly Cloudy | 10 to 15 mph NE | 18% |
| Tuesday | 62°F | Slight Chance Rain Showers | 10 to 15 mph NE | 16% |
| Tuesday Night | 49°F | Partly Cloudy | 5 to 15 mph NE | 13% |
| Wednesday | 65°F | Mostly Sunny | 10 to 15 mph NE | 5% |
| Wednesday Night | 50°F | Partly Cloudy | 5 to 10 mph NNE | 1% |
| Thursday | 67°F | Partly Sunny | 5 to 10 mph NNE | 4% |
| Thursday Night | 51°F | Mostly Cloudy | 5 to 10 mph NE | 4% |
| Friday | 71°F | Mostly Sunny | 5 to 10 mph NE | 4% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Sycamore, IL
Last spring frost
Apr 24
First fall frost
Oct 18
Growing season
177 days
Hardiness zone
5b
Explore more for Sycamore, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, De Kalb, Il (7.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.