Lake Forest, IL Weather & Growing Conditions
Today
84°F
Mostly Sunny
Mostly sunny, with a high near 84. South southwest wind around 10 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 84°F | Mostly Sunny | 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). 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 Aug 4, 2026.