Crystal Lake, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Crystal Lake, a city in Mchenry County, Illinois.
This Afternoon
69°F
Rain Likely
Rain likely and a slight chance of thunderstorms. Mostly cloudy. High near 69, with temperatures falling to around 66 in the afternoon. South wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 70%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Crystal Lake
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 69°F | Rain Likely | 15 to 20 mph S | 69% |
| Tonight | 59°F | Rain | 15 mph S | 81% |
| Wednesday | 62°F | Rain Likely | 15 mph SSW | 59% |
| Wednesday Night | 47°F | Slight Chance Rain | 15 mph SW | 22% |
| Thursday | 55°F | Chance Rain | 10 to 15 mph WSW | 42% |
| Thursday Night | 41°F | Chance Rain | 5 to 10 mph NW | 50% |
| Friday | 51°F | Slight Chance Rain | 10 to 15 mph N | 23% |
| Friday Night | 35°F | Mostly Cloudy | 0 to 5 mph NNW | 3% |
| Saturday | 51°F | Mostly Sunny | 0 to 5 mph WNW | 5% |
| Saturday Night | 34°F | Partly Cloudy | 0 to 5 mph WSW | 7% |
| Sunday | 56°F | Mostly Sunny then Slight Chance Rain | 5 mph W | 17% |
| Sunday Night | 36°F | Mostly Clear | 5 mph W | 7% |
| Monday | 60°F | Sunny | 5 to 10 mph WSW | 3% |
| Monday Night | 40°F | Mostly Clear | 5 mph W | 2% |
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 Nov 3, 2026.