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. High near 70, with temperatures falling to around 66 in the afternoon. South wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Winthrop Harbor
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 70°F | Chance Rain Showers | 15 mph S | 38% |
| Tonight | 59°F | Rain Showers | 15 mph SSE | 75% |
| Wednesday | 63°F | Rain Showers Likely | 15 mph SSW | 65% |
| Wednesday Night | 47°F | Mostly Cloudy then Slight Chance Rain Showers | 15 mph SW | 19% |
| Thursday | 55°F | Chance Rain Showers | 10 to 15 mph WSW | 45% |
| Thursday Night | 41°F | Rain Showers Likely | 10 to 15 mph NW | 65% |
| Friday | 51°F | Chance Rain Showers | 15 to 20 mph N | 33% |
| Friday Night | 36°F | Mostly Cloudy | 5 to 10 mph NNW | 13% |
| Saturday | 52°F | Mostly Sunny | 5 mph WNW | 7% |
| Saturday Night | 36°F | Partly Cloudy | 5 mph WSW | 7% |
| Sunday | 56°F | Mostly Sunny then Slight Chance Rain | 5 to 10 mph W | 17% |
| Sunday Night | 36°F | Partly Cloudy | 5 mph WNW | 8% |
| Monday | 58°F | Sunny | 5 to 10 mph WSW | 4% |
| Monday Night | 40°F | Partly Cloudy | 5 to 10 mph W | 3% |
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
Antioch
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Buffalo Grove
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Deerfield
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Island Lake
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Lake Zurich
Libertyville
Lincolnshire
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 Nov 4, 2026.