North Liberty, IA 52317 Frost Dates
North Liberty, IA: when does the frost end?
Around 04/21 is the usual last spring frost, about 236 days away. Fall's first freeze usually shows up around 10/18, roughly 180 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 North Liberty, not a forecast for this year.
Stretching the season past the first frost
With roughly 7 weeks until North Liberty's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/21 isn't a guarantee
04/21 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 05/06 and only about 1 year in 10 sees frost after that.
North Liberty against the rest of the dataset
North Liberty's growing season runs about 180 days, ranking 24,799 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 90 of 1,042.
Learn more
Before leaning on 52317's figures: the frost range explains how to read the range around North Liberty's dates instead of trusting one, while local microclimates explains what one yard in North Liberty can differ from the 52317 normal.