Lacon, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lacon, a city in Marshall County, Illinois.
This Afternoon
69°F
Light Rain
Rain and a slight chance of thunderstorms. Mostly cloudy, with a high near 69. South wind around 15 mph, with gusts as high as 31 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Lacon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 69°F | Light Rain | 15 mph S | 80% |
| Tonight | 53°F | Light Rain | 9 to 13 mph S | 85% |
| Wednesday | 57°F | Chance Light Rain then Mostly Cloudy | 13 mph SW | 26% |
| Wednesday Night | 44°F | Mostly Cloudy | 9 mph SW | 7% |
| Thursday | 56°F | Mostly Cloudy then Slight Chance Light Rain | 7 to 10 mph WSW | 16% |
| Thursday Night | 40°F | Chance Light Rain | 2 to 6 mph NW | 29% |
| Friday | 52°F | Slight Chance Light Rain | 8 mph N | 19% |
| Friday Night | 33°F | Partly Cloudy | 0 to 6 mph NNW | 3% |
| Saturday | 52°F | Mostly Sunny | 0 to 3 mph WNW | 2% |
| Saturday Night | 33°F | Partly Cloudy | 2 mph W | 4% |
| Sunday | 58°F | Sunny then Slight Chance Light Rain | 2 to 7 mph W | 15% |
| Sunday Night | 33°F | Mostly Clear | 5 mph W | 4% |
| Monday | 62°F | Sunny | 2 to 9 mph SW | 2% |
| Monday Night | 37°F | Mostly Clear | 6 mph WSW | 1% |
Forecast source: National Weather Service (api.weather.gov) for Lacon (41.023, -89.406). Updated through the day.
Growing snapshot for Lacon
Last spring frost
Apr 20
First fall frost
Oct 17
Growing season
178 days
Hardiness zone
5b
More local growing data for Lacon: nearby ZIP 61540 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Lacon, Il (2.6 mi from Lacon). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 3, 2026.