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
70°F
Chance Rain
A chance of rain before 3pm, then a chance of rain and a slight chance of thunderstorms. Mostly cloudy. High near 70, with temperatures falling to around 67 in the afternoon. South wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Lake Forest
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 70°F | Chance Rain | 15 to 20 mph S | 38% |
| Tonight | 60°F | Rain | 15 mph S | 76% |
| Wednesday | 63°F | Rain Likely | 15 mph SSW | 61% |
| Wednesday Night | 48°F | Slight Chance Rain then Mostly Cloudy | 15 mph SW | 17% |
| Thursday | 56°F | Chance Rain | 10 to 15 mph WSW | 34% |
| Thursday Night | 42°F | Rain Likely | 10 to 15 mph WNW | 63% |
| Friday | 52°F | Chance Rain | 15 mph N | 35% |
| Friday Night | 37°F | Mostly Cloudy | 5 to 10 mph NNW | 13% |
| Saturday | 52°F | Mostly Sunny | 5 mph WNW | 9% |
| Saturday Night | 36°F | Partly Cloudy | 0 to 5 mph WSW | 7% |
| Sunday | 56°F | Mostly Sunny then Slight Chance Rain | 5 to 10 mph W | 17% |
| Sunday Night | 37°F | Mostly Clear | 5 mph WNW | 9% |
| Monday | 58°F | Mostly Sunny | 5 to 10 mph W | 5% |
| Monday Night | 41°F | Mostly Clear | 5 to 10 mph W | 3% |
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 Nov 3, 2026.