Seneca, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Seneca, a village in Lasalle County, Illinois.
This Afternoon
71°F
Rain Showers Likely
Rain showers likely. Mostly cloudy. High near 71, with temperatures falling to around 68 in the afternoon. South wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 60%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Seneca
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 71°F | Rain Showers Likely | 15 mph S | 58% |
| Tonight | 59°F | Rain Showers | 15 mph S | 90% |
| Wednesday | 62°F | Chance Rain Showers then Mostly Cloudy | 15 mph SSW | 43% |
| Wednesday Night | 48°F | Mostly Cloudy | 10 to 15 mph SW | 11% |
| Thursday | 58°F | Mostly Cloudy then Slight Chance Rain Showers | 10 to 15 mph WSW | 24% |
| Thursday Night | 44°F | Chance Rain Showers | 5 to 10 mph NW | 35% |
| Friday | 54°F | Slight Chance Rain Showers | 10 mph N | 24% |
| Friday Night | 37°F | Partly Cloudy | 0 to 5 mph NNW | 3% |
| Saturday | 52°F | Mostly Sunny | 0 to 5 mph WNW | 4% |
| Saturday Night | 36°F | Partly Cloudy | 0 mph | 3% |
| Sunday | 58°F | Sunny | 0 to 10 mph W | 12% |
| Sunday Night | 36°F | Mostly Clear | 0 to 5 mph W | 7% |
| Monday | 62°F | Sunny | 0 to 10 mph WSW | 3% |
| Monday Night | 41°F | Mostly Clear | 5 mph WSW | 1% |
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 Nov 4, 2026.