Rockville, MN 56369 Frost Dates
Rockville, MN: when does the frost end?
Around 05/03 is the usual last spring frost, about 248 days away. Fall's first freeze usually shows up around 10/07, roughly 155 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Rockville in Zone 4b (-25 to -20°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 Rockville's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/03 isn't a guarantee
05/03 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/21 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/17 and only about 1 year in 10 sees frost after that.
Rockville against the rest of the dataset
About 155 days separate Rockville's last and first frost, putting it 33,992 of 40,283 ZIP codes nationally. Within MN, it ranks 352 of 943.
Learn more
Before leaning on 56369's figures: local microclimates explains what one yard in Rockville can differ from the 56369 normal, while zone vs. frost date explains why Zone 4b and Rockville's frost date answer different questions.