Houghton, MI 49921 Frost Dates
Houghton, MI: when does the frost end?
Around 05/17 is the usual last spring frost, about 262 days away. Fall's first freeze usually shows up around 10/01, roughly 138 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Houghton in Zone 5b (-15 to -10°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 5 weeks until Houghton's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Houghton's last frost
05/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/01 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/03 and only about 1 year in 10 sees frost after that.
Houghton against the rest of the dataset
About 138 days separate Houghton's last and first frost, putting it 37,372 of 40,283 ZIP codes nationally. Within MI, it ranks 920 of 1,153.
Learn more
Before leaning on 49921's figures: zone vs. frost date explains why Zone 5b and Houghton's frost date answer different questions, while the frost range explains how to read the range around Houghton's dates instead of trusting one.