Seneca, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Seneca, a village in Lasalle County, Illinois.
Overnight
63°F
Mostly Clear
Mostly clear. Low around 63, with temperatures rising to around 65 overnight. South wind around 5 mph.
7-day forecast for Seneca
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 63°F | Mostly Clear | 5 mph S | 0% |
| Tuesday | 85°F | Mostly Sunny | 5 mph SSW | 5% |
| Tuesday Night | 68°F | Mostly Cloudy | 5 mph S | 10% |
| Wednesday | 82°F | Chance Showers And Thunderstorms | 0 to 5 mph WSW | 55% |
| Wednesday Night | 67°F | Showers And Thunderstorms | 0 to 5 mph NW | 90% |
| Thursday | 80°F | Chance Showers And Thunderstorms | 0 to 5 mph SE | 72% |
| Thursday Night | 65°F | Chance Showers And Thunderstorms then Partly Cloudy | 0 to 5 mph SSE | 28% |
| Friday | 83°F | Mostly Sunny | 0 to 5 mph S | 6% |
| Friday Night | 66°F | Partly Cloudy | 0 mph | 8% |
| Saturday | 85°F | Mostly Sunny | 0 to 5 mph SSW | 11% |
| Saturday Night | 71°F | Mostly Clear | 5 mph SSW | 11% |
| Sunday | 88°F | Mostly Sunny | 5 to 10 mph SW | 9% |
| Sunday Night | 72°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SSW | 30% |
| Monday | 87°F | Chance Showers And Thunderstorms | 5 to 10 mph SSW | 30% |
Forecast source: National Weather Service (api.weather.gov) for Seneca (41.303, -88.615). Updated through the day.
Growing snapshot for Seneca
Last spring frost
Apr 27
First fall frost
Oct 17
Growing season
171 days
Hardiness zone
5b
More local growing data for Seneca: nearby ZIP 61360 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Cedar Point
Dana
Dayton
Earlville
Grand Ridge
Harding
Kangley
LaSalle
Leland
Leonore
Lostant
Marseilles
Mendota
Millington
Naplate
Newark
North Utica
Oglesby
Ottawa
Peru
Ransom
Rutland
Serena
Sheridan
Streator
Tonica
Triumph
Troy Grove
Wedron
Wenona
Climate data from the nearest NOAA station, Marseilles Lock, Il (7.9 mi from Seneca). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.