Crystal Lake, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Crystal Lake, a city in Mchenry County, Illinois.
Tonight
61°F
Slight Chance Rain Showers then Showers And Thunderstorms Likely
A slight chance of rain showers before midnight, then showers and thunderstorms likely. Some of the storms could produce heavy rain. Cloudy, with a low around 61. East southeast 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 for Crystal Lake
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 61°F | Slight Chance Rain Showers then Showers And Thunderstorms Likely | 10 to 15 mph ESE | 65% |
| Saturday | 75°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 10 to 15 mph ESE | 94% |
| Saturday Night | 62°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 5 to 10 mph NE | 79% |
| Sunday | 67°F | Showers And Thunderstorms Likely | 10 to 15 mph NE | 73% |
| Sunday Night | 55°F | Chance Rain Showers | 15 mph ENE | 47% |
| Monday | 63°F | Chance Rain Showers | 15 mph ENE | 40% |
| Monday Night | 51°F | Chance Rain Showers | 10 to 15 mph ENE | 40% |
| Tuesday | 61°F | Slight Chance Rain Showers | 10 to 15 mph NE | 19% |
| Tuesday Night | 51°F | Mostly Cloudy | 5 to 10 mph NE | 14% |
| Wednesday | 64°F | Partly Sunny | 5 to 10 mph NNE | 9% |
| Wednesday Night | 51°F | Mostly Cloudy | 0 to 5 mph NNE | 5% |
| Thursday | 67°F | Partly Sunny | 0 to 5 mph NNE | 5% |
| Thursday Night | 52°F | Mostly Cloudy | 0 to 5 mph NNE | 4% |
| Friday | 69°F | Mostly Sunny | 0 to 5 mph NNE | 5% |
Forecast source: National Weather Service (api.weather.gov) for Crystal Lake (42.233, -88.334). Updated through the day.
Growing snapshot for Crystal Lake
Last spring frost
Apr 25
First fall frost
Oct 22
Growing season
179 days
Hardiness zone
5b
More local growing data for Crystal Lake: nearby ZIP 60014 weather · frost dates · planting calendar · Illinois frost dates
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Climate data from the nearest NOAA station, Crystal Lake 4Nw, Il (4 mi from Crystal Lake). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.