Grayslake, IL Weather & Growing Conditions
Today
83°F
Mostly Sunny
Mostly sunny, with a high near 83. Southwest wind around 10 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 83°F | Mostly Sunny | 10 mph SW | 0% |
| Tonight | 66°F | Mostly Cloudy then Chance Showers And Thunderstorms | 5 to 10 mph WSW | 47% |
| Wednesday | 78°F | Showers And Thunderstorms Likely | 5 mph SW | 74% |
| Wednesday Night | 61°F | Showers And Thunderstorms | 0 to 5 mph WNW | 80% |
| Thursday | 78°F | Chance Rain Showers | 0 to 5 mph NNE | 52% |
| Thursday Night | 59°F | Partly Cloudy | 0 to 5 mph NE | 13% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph SSW | 3% |
| Friday Night | 62°F | Mostly Clear | 0 to 5 mph S | 8% |
| Saturday | 83°F | Mostly Sunny | 5 to 10 mph SW | 10% |
| Saturday Night | 68°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SW | 21% |
| Sunday | 84°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 21% |
| Sunday Night | 67°F | Chance Showers And Thunderstorms | 5 to 10 mph WSW | 46% |
| Monday | 83°F | Chance Rain Showers | 5 mph SSW | 46% |
| Monday Night | 67°F | Chance Showers And Thunderstorms | 5 mph NW | 47% |
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 Aug 4, 2026.