Sycamore, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sycamore, a city in Dekalb County, Illinois.
Overnight
62°F
Mostly Clear
Mostly clear, with a low around 62. South wind around 5 mph.
7-day forecast for Sycamore
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 62°F | Mostly Clear | 5 mph S | 0% |
| Tuesday | 84°F | Mostly Sunny | 5 to 10 mph SSW | 0% |
| Tuesday Night | 66°F | Mostly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SW | 56% |
| Wednesday | 77°F | Showers And Thunderstorms Likely | 0 to 5 mph WSW | 74% |
| Wednesday Night | 62°F | Showers And Thunderstorms | 0 to 5 mph NW | 82% |
| Thursday | 78°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 0 to 5 mph NE | 54% |
| Thursday Night | 60°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 to 5 mph SE | 19% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph SSE | 7% |
| Friday Night | 63°F | Mostly Clear | 0 to 5 mph SSW | 9% |
| Saturday | 83°F | Mostly Sunny | 5 to 10 mph SSW | 10% |
| Saturday Night | 68°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 to 10 mph SSW | 19% |
| Sunday | 85°F | Slight Chance Showers And Thunderstorms | 10 to 15 mph SW | 19% |
| Sunday Night | 68°F | Chance Showers And Thunderstorms | 5 to 10 mph SSW | 41% |
| Monday | 84°F | Chance Rain Showers | 5 to 10 mph SSW | 40% |
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 Aug 4, 2026.