Oswego, IL 60543 Frost Dates
Oswego, 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 10/23, roughly 185 days after the last spring frost.
Zone 5b (-15 to -10°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Oswego, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Oswego's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Oswego's last frost
04/19 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/04 and only about 1 year in 10 sees frost after that.
Oswego against the rest of the dataset
At roughly 185 frost-free days, Oswego places 23,056 of 40,283 ZIP codes in this dataset. Within IL, it ranks 819 of 1,548.
Learn more
Before leaning on 60543's figures: local microclimates explains what one yard in Oswego can differ from the 60543 normal, while zone vs. frost date explains why Zone 5b and Oswego's frost date answer different questions.