Lake Forest, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lake Forest, a city in Lake County, Illinois.
Today
84°F
Mostly Sunny
Mostly sunny, with a high near 84. South southwest wind 5 to 10 mph, with gusts as high as 20 mph.
7-day forecast for Lake Forest
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 84°F | Mostly Sunny | 5 to 10 mph SSW | 0% |
| Tonight | 69°F | Mostly Cloudy then Chance Showers And Thunderstorms | 5 to 10 mph SW | 39% |
| Wednesday | 78°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 mph W | 74% |
| Wednesday Night | 64°F | Showers And Thunderstorms | 0 to 5 mph NNW | 85% |
| Thursday | 76°F | Rain Showers Likely then Slight Chance Showers And Thunderstorms | 0 to 5 mph NNE | 58% |
| Thursday Night | 63°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 to 5 mph S | 15% |
| Friday | 80°F | Mostly Sunny | 0 to 5 mph SW | 3% |
| Friday Night | 65°F | Mostly Clear | 0 to 5 mph S | 8% |
| Saturday | 85°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 5 mph SSW | 15% |
| Saturday Night | 70°F | Slight Chance Showers And Thunderstorms | 5 mph SW | 22% |
| Sunday | 86°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 22% |
| Sunday Night | 68°F | Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms | 5 to 10 mph SW | 47% |
| Monday | 84°F | Chance Showers And Thunderstorms | 5 mph SSW | 47% |
| Monday Night | 68°F | Chance Showers And Thunderstorms | 5 mph W | 49% |
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 Aug 4, 2026.