Sycamore, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sycamore, a city in Dekalb County, Illinois.
This Afternoon
72°F
Slight Chance Rain Showers
A slight chance of rain showers. Mostly cloudy. High near 72, with temperatures falling to around 70 in the afternoon. East wind around 15 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Sycamore
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 72°F | Slight Chance Rain Showers | 15 mph E | 20% |
| Tonight | 62°F | Slight Chance Rain Showers then Chance Showers And Thunderstorms | 10 mph ESE | 54% |
| Saturday | 76°F | Showers And Thunderstorms Likely | 5 to 15 mph SE | 88% |
| Saturday Night | 63°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 5 to 10 mph ENE | 80% |
| Sunday | 68°F | Showers And Thunderstorms | 10 to 15 mph NNE | 77% |
| Sunday Night | 55°F | Rain Showers Likely | 15 mph NE | 57% |
| Monday | 64°F | Chance Rain Showers | 15 mph ENE | 47% |
| Monday Night | 50°F | Chance Rain Showers | 10 to 15 mph ENE | 34% |
| Tuesday | 63°F | Chance Rain Showers | 10 to 15 mph NE | 26% |
| Tuesday Night | 49°F | Mostly Cloudy | 5 to 15 mph NE | 11% |
| Wednesday | 66°F | Partly Sunny | 5 to 10 mph NNE | 6% |
| Wednesday Night | 50°F | Mostly Cloudy | 5 to 10 mph NNE | 5% |
| Thursday | 69°F | Partly Sunny | 5 to 10 mph NNE | 4% |
| Thursday Night | 51°F | Mostly Cloudy | 0 to 5 mph NNE | 4% |
Forecast source: National Weather Service (api.weather.gov) for Sycamore (41.997, -88.678). Updated through the day.
Growing snapshot for Sycamore
Last spring frost
Apr 24
First fall frost
Oct 18
Growing season
177 days
Hardiness zone
5b
More local growing data for Sycamore: nearby ZIP 60178 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Cortland
DeKalb
Genoa
Hinckley
Kingston
Kirkland
Lake Holiday
Malta
Sandwich
Shabbona
Somonauk
Waterman
Climate data from the nearest NOAA station, De Kalb, Il (7.8 mi from Sycamore). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.