Hopkinton, IA 52237 Frost Dates
Hopkinton, IA: when does the frost end?
Around 04/28 is the usual last spring frost, about 243 days away. Fall's first freeze usually shows up around 10/10, roughly 164 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Hopkinton in Zone 5a (-20 to -15°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 Hopkinton's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
04/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/12 and only about 1 year in 10 sees frost after that.
Hopkinton against the rest of the dataset
At roughly 164 frost-free days, Hopkinton places 31,104 of 40,283 ZIP codes in this dataset. Within IA, it ranks 612 of 1,042.
Learn more
Before leaning on 52237's figures: local microclimates explains what one yard in Hopkinton can differ from the 52237 normal, while zone vs. frost date explains why Zone 5a and Hopkinton's frost date answer different questions.