Winthrop Harbor, IL 53141 Frost Dates
Winthrop Harbor, IL: when does the frost end?
The last spring frost here typically falls around 04/19, about 234 days from today. Fall's first freeze usually shows up around 10/26, roughly 189 days after the last spring frost.
Winthrop Harbor sits in USDA Zone 6a (-10 to -5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
With roughly 8 weeks until Winthrop Harbor's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Winthrop Harbor's last frost
04/19 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/06 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/03 and only about 1 year in 10 sees frost after that.
Winthrop Harbor against the rest of the dataset
About 189 days separate Winthrop Harbor's last and first frost, putting it 21,520 of 40,283 ZIP codes nationally. Within IL, it ranks 582 of 1,548.
Learn more
Before leaning on 53141's figures: local microclimates explains what one yard in Winthrop Harbor can differ from the 53141 normal, while zone vs. frost date explains why Zone 6a and Winthrop Harbor's frost date answer different questions.