Marshall, MI 49020 Frost Dates
49020, near Marshall, MI: the frost window
Around 04/30 is the usual last spring frost, about 245 days away. Fall's first freeze usually shows up around 10/19, roughly 170 days after the last spring frost.
Zone 6a (-10 to -5°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 Marshall, not a forecast for this year.
Stretching the season past the first frost
Marshall's growing season runs out in roughly 7 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
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/16 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.
Marshall against the rest of the dataset
Marshall's growing season runs about 170 days, ranking 28,961 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 310 of 1,153.
Learn more
Two guides worth reading on 49020: local microclimates, on what one yard in Marshall can differ from the 49020 normal, and zone vs. frost date, on why Zone 6a and Marshall's frost date answer different questions.