Lake Forest, IL Weather & Growing Conditions
Overnight
62°F
Showers And Thunderstorms
Showers and thunderstorms. Some of the storms could produce heavy rain. Cloudy. Low around 62, with temperatures rising to around 64 overnight. East southeast wind around 15 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 62°F | Showers And Thunderstorms | 15 mph ESE | 97% |
| Saturday | 75°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 15 mph SSE | 100% |
| Saturday Night | 61°F | Showers And Thunderstorms | 5 to 10 mph E | 94% |
| Sunday | 69°F | Showers And Thunderstorms Likely | 15 to 20 mph NNE | 56% |
| Sunday Night | 55°F | Mostly Cloudy | 15 to 20 mph NE | 14% |
| Monday | 65°F | Slight Chance Rain Showers | 15 to 20 mph ENE | 19% |
| Monday Night | 53°F | Mostly Cloudy | 15 to 20 mph ENE | 10% |
| Tuesday | 64°F | Mostly Cloudy | 15 to 20 mph NE | 11% |
| Tuesday Night | 53°F | Mostly Cloudy | 10 to 15 mph NE | 8% |
| Wednesday | 64°F | Partly Sunny | 10 to 15 mph NE | 13% |
| Wednesday Night | 54°F | Mostly Cloudy | 5 to 10 mph NE | 6% |
| Thursday | 66°F | Partly Sunny | 5 to 10 mph NNE | 4% |
| Thursday Night | 54°F | Mostly Cloudy | 5 mph NNE | 3% |
| Friday | 68°F | Partly Sunny | 5 to 10 mph NE | 4% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Lake Forest, IL
Last spring frost
Apr 26
First fall frost
Oct 21
Growing season
176 days
Hardiness zone
6a
Explore more for Lake Forest, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Chicago Botanic Garden, Il (7.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.