Lacon, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lacon, a city in Marshall County, Illinois.
Tonight
67°F
Partly Cloudy then Chance Showers And Thunderstorms
A chance of showers and thunderstorms after 3am. Partly cloudy, with a low around 67. East southeast wind around 7 mph, with gusts as high as 16 mph. Chance of precipitation is 30%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Lacon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 67°F | Partly Cloudy then Chance Showers And Thunderstorms | 7 mph ESE | 31% |
| Saturday | 83°F | Chance Showers And Thunderstorms | 8 mph SSE | 43% |
| Saturday Night | 66°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 2 to 6 mph N | 69% |
| Sunday | 74°F | Rain Showers | 5 to 10 mph NNE | 76% |
| Sunday Night | 56°F | Showers And Thunderstorms Likely | 12 mph NE | 73% |
| Monday | 66°F | Showers And Thunderstorms Likely | 13 mph ENE | 67% |
| Monday Night | 52°F | Chance Rain Showers | 10 to 16 mph NE | 44% |
| Tuesday | 64°F | Chance Rain Showers | 10 to 14 mph NE | 28% |
| Tuesday Night | 49°F | Mostly Cloudy | 5 to 13 mph NNE | 6% |
| Wednesday | 68°F | Partly Sunny | 6 to 9 mph NNE | 5% |
| Wednesday Night | 51°F | Partly Cloudy | 2 to 7 mph NNE | 5% |
| Thursday | 69°F | Mostly Sunny | 2 to 7 mph NNE | 3% |
| Thursday Night | 53°F | Partly Cloudy | 1 to 5 mph NNE | 4% |
| Friday | 71°F | Mostly Sunny | 2 to 6 mph NNE | 4% |
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 Sep 19, 2026.