Lanark, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lanark, a city in Carroll County, Illinois.
Tonight
52°F
Rain Showers Likely
Rain showers likely. Mostly cloudy. Low around 52, with temperatures rising to around 55 overnight. South wind 10 to 15 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast for Lanark
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 52°F | Rain Showers Likely | 10 to 15 mph S | 62% |
| Wednesday | 57°F | Chance Rain Showers | 15 mph SW | 44% |
| Wednesday Night | 44°F | Chance Rain Showers | 15 mph SW | 27% |
| Thursday | 54°F | Chance Rain Showers | 10 to 15 mph W | 51% |
| Thursday Night | 38°F | Slight Chance Rain Showers then Mostly Cloudy | 10 mph N | 16% |
| Friday | 49°F | Partly Sunny | 5 to 15 mph N | 4% |
| Friday Night | 29°F | Mostly Clear | 0 to 5 mph N | 0% |
| Saturday | 51°F | Sunny | 0 to 5 mph NW | 0% |
| Saturday Night | 32°F | Mostly Clear | 0 to 5 mph W | 2% |
| Sunday | 56°F | Sunny | 5 to 10 mph W | 4% |
| Sunday Night | 33°F | Mostly Clear | 0 to 5 mph W | 0% |
| Monday | 60°F | Sunny | 0 to 10 mph SW | 0% |
| Monday Night | 38°F | Mostly Clear | 5 mph W | 0% |
| Tuesday | 61°F | Sunny | 5 mph NW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Lanark (42.102, -89.833). Updated through the day.
Growing snapshot for Lanark
Last spring frost
May 2
First fall frost
Oct 7
Growing season
154 days
Hardiness zone
5a
More local growing data for Lanark: nearby ZIP 61046 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Mt Carroll, Il (8.8 mi from Lanark). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.