South Beloit, IL 61080 Frost Dates
South Beloit, IL: when does the frost end?
Around 05/01 is the usual last spring frost, about 246 days away. Fall's first freeze usually shows up around 10/12, roughly 162 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts South Beloit in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 6 weeks until South Beloit's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around South Beloit's last frost
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/16 and only about 1 year in 10 sees frost after that.
South Beloit against the rest of the dataset
South Beloit's growing season runs about 162 days, ranking 31,701 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 1,533 of 1,548.
Learn more
Before leaning on 61080's figures: local microclimates explains what one yard in South Beloit can differ from the 61080 normal, while zone vs. frost date explains why Zone 5b and South Beloit's frost date answer different questions.