Winthrop Harbor, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Winthrop Harbor, a village in Lake County, Illinois.
This Afternoon
70°F
Chance Rain Showers
A chance of rain showers. Mostly cloudy, with a high near 70. East wind around 15 mph. Chance of precipitation is 30%.
7-day forecast for Winthrop Harbor
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 70°F | Chance Rain Showers | 15 mph E | 27% |
| Tonight | 60°F | Showers And Thunderstorms Likely | 15 to 20 mph E | 82% |
| Saturday | 74°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 15 to 20 mph SE | 97% |
| Saturday Night | 62°F | Showers And Thunderstorms Likely then Showers And Thunderstorms | 10 to 15 mph NE | 77% |
| Sunday | 67°F | Showers And Thunderstorms Likely | 15 to 25 mph NNE | 67% |
| Sunday Night | 54°F | Chance Rain Showers | 20 mph NE | 39% |
| Monday | 65°F | Chance Rain Showers | 20 to 25 mph ENE | 34% |
| Monday Night | 52°F | Chance Rain Showers | 10 to 20 mph ENE | 32% |
| Tuesday | 64°F | Slight Chance Rain Showers | 15 mph NE | 20% |
| Tuesday Night | 52°F | Slight Chance Rain Showers then Mostly Cloudy | 10 to 15 mph ENE | 18% |
| Wednesday | 65°F | Partly Sunny | 10 mph NE | 13% |
| Wednesday Night | 52°F | Mostly Cloudy | 5 to 10 mph NNE | 5% |
| Thursday | 66°F | Partly Sunny | 5 to 10 mph NNE | 5% |
| Thursday Night | 53°F | Mostly Cloudy | 5 mph NNE | 5% |
Forecast source: National Weather Service (api.weather.gov) for Winthrop Harbor (42.481, -87.830). Updated through the day.
Growing snapshot for Winthrop Harbor
Last spring frost
Apr 30
First fall frost
Oct 21
Growing season
173 days
Hardiness zone
6a
More local growing data for Winthrop Harbor: nearby ZIP 60096 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
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Climate data from the nearest NOAA station, Chicago Waukegan Rgnl Ap, Il (4.8 mi from Winthrop Harbor). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.