Grayslake, IL Weather & Growing Conditions
Tonight
60°F
Slight Chance Rain Showers then Showers And Thunderstorms Likely
A slight chance of rain showers before midnight, then showers and thunderstorms likely. Mostly cloudy, with a low around 60. East wind 10 to 15 mph. Chance of precipitation is 70%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 60°F | Slight Chance Rain Showers then Showers And Thunderstorms Likely | 10 to 15 mph E | 71% |
| Saturday | 75°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 10 to 15 mph ESE | 95% |
| Saturday Night | 62°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 5 to 10 mph NE | 78% |
| Sunday | 67°F | Showers And Thunderstorms Likely | 10 to 20 mph NE | 71% |
| Sunday Night | 54°F | Chance Rain Showers | 15 mph NE | 44% |
| Monday | 63°F | Chance Rain Showers | 15 mph ENE | 39% |
| Monday Night | 50°F | Chance Rain Showers | 10 to 15 mph ENE | 37% |
| Tuesday | 62°F | Slight Chance Rain Showers | 10 to 15 mph NE | 20% |
| Tuesday Night | 50°F | Slight Chance Rain Showers then Mostly Cloudy | 5 to 10 mph NE | 17% |
| Wednesday | 64°F | Partly Sunny | 5 to 10 mph NE | 11% |
| Wednesday Night | 50°F | Mostly Cloudy | 5 mph NNE | 4% |
| Thursday | 66°F | Partly Sunny | 5 mph NNE | 5% |
| Thursday Night | 51°F | Mostly Cloudy | 0 to 5 mph N | 4% |
| Friday | 69°F | Mostly Sunny | 0 to 5 mph NNE | 4% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Grayslake, IL
Last spring frost
Apr 29
First fall frost
Oct 20
Growing season
172 days
Hardiness zone
5b
Explore more for Grayslake, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Mundelein 4 Wsw, Il (5.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.