Lake Forest, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lake Forest, a city in Lake County, Illinois.
This Afternoon
71°F
Slight Chance Rain Showers
A slight chance of rain showers. Mostly cloudy. High near 71, with temperatures falling to around 69 in the afternoon. East wind around 15 mph. Chance of precipitation is 20%.
7-day forecast for Lake Forest
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 71°F | Slight Chance Rain Showers | 15 mph E | 20% |
| Tonight | 61°F | Slight Chance Rain Showers then Showers And Thunderstorms Likely | 15 mph E | 63% |
| Saturday | 75°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 10 to 15 mph SE | 94% |
| Saturday Night | 62°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 10 mph NE | 80% |
| Sunday | 67°F | Showers And Thunderstorms Likely | 15 to 20 mph NNE | 74% |
| Sunday Night | 55°F | Chance Rain Showers | 15 to 20 mph NE | 47% |
| Monday | 65°F | Chance Rain Showers | 15 to 20 mph ENE | 42% |
| Monday Night | 53°F | Chance Rain Showers | 10 to 20 mph ENE | 33% |
| Tuesday | 64°F | Slight Chance Rain Showers | 15 mph NE | 21% |
| Tuesday Night | 53°F | Slight Chance Rain Showers then Mostly Cloudy | 10 to 15 mph NE | 20% |
| Wednesday | 65°F | Mostly Cloudy | 10 mph NE | 12% |
| Wednesday Night | 53°F | Mostly Cloudy | 5 to 10 mph NNE | 4% |
| Thursday | 67°F | Partly Sunny | 5 to 10 mph NNE | 7% |
| Thursday Night | 54°F | Mostly Cloudy | 5 mph NNE | 5% |
Forecast source: National Weather Service (api.weather.gov) for Lake Forest (42.235, -87.857). Updated through the day.
Growing snapshot for Lake Forest
Last spring frost
Apr 26
First fall frost
Oct 21
Growing season
176 days
Hardiness zone
6a
More local growing data for Lake Forest: nearby ZIP 60045 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Antioch
Bannockburn
Beach Park
Buffalo Grove
Burtons Bridge
Deer Park
Deerfield
Forest Lake
Fox Lake
Fox Lake Hills
Gages Lake
Grandwood Park
Grayslake
Green Oaks
Gurnee
Hainesville
Hawthorn Woods
Highland Park
Highwood
Holiday Hills
Indian Creek
Island Lake
Kildeer
Knollwood
Lake Bluff
Lake Villa
Lake Zurich
Libertyville
Lincolnshire
Lindenhurst
Climate data from the nearest NOAA station, Chicago Botanic Garden, Il (7.8 mi from Lake Forest). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.