Andover, IL 61233 Frost Dates
Andover, IL: when does the frost end?
Typically, the last spring freeze lands around 04/20, roughly 235 days out. Fall's first freeze usually shows up around 10/20, roughly 180 days after the last spring frost.
Andover sits in USDA Zone 5b (-15 to -10°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 Andover's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Andover's last frost
04/20 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 05/06 and only about 1 year in 10 sees frost after that.
Andover against the rest of the dataset
Andover's growing season runs about 180 days, ranking 25,013 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 971 of 1,548.
Learn more
Before leaning on 61233's figures: zone vs. frost date explains why Zone 5b and Andover's frost date answer different questions, while the frost range explains how to read the range around Andover's dates instead of trusting one.