Harman US

Lake Forest, IL Weather & Growing Conditions

Today
75°F
Showers And Thunderstorms
Showers and thunderstorms before 1pm, then a chance of showers and thunderstorms between 1pm and 5pm, then showers and thunderstorms likely. Cloudy. High near 75, with temperatures falling to around 72 in the afternoon. South wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 100%. New rainfall amounts between three quarters and one inch possible.

7-day forecast

WhenTempForecastWindPrecip
Today 75°F Showers And Thunderstorms 5 to 10 mph S 98%
Tonight 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%
Friday Night 54°F Partly Cloudy 5 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.