Cromwell, MN 55726 Frost Dates
55726, near Cromwell, MN: the frost window
The last spring frost here typically falls around 05/31, about 276 days from today. Fall's first freeze usually shows up around 09/18, roughly 107 days after the last spring frost.
Zone 4a (-30 to -25°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 Cromwell, not a forecast for this year.
Stretching the season past the first frost
Cromwell's growing season runs out in roughly 3 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
05/31 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/20 and only about 1 year in 10 sees frost after that.
Cromwell against the rest of the dataset
At roughly 107 frost-free days, Cromwell places 39,569 of 40,283 ZIP codes in this dataset. Within MN, it ranks 916 of 943.
Learn more
Two guides worth reading on 55726: local microclimates, on what one yard in Cromwell can differ from the 55726 normal, and zone vs. frost date, on why Zone 4a and Cromwell's frost date answer different questions.