Whittemore, MI 48739 Frost Dates
48739, near Whittemore, MI: the frost window
Around 05/23 is the usual last spring frost, about 268 days away. Fall's first freeze usually shows up around 09/26, roughly 127 days after the last spring frost.
Whittemore sits in USDA Zone 5a (-20 to -15°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Whittemore's growing season runs out in roughly 4 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/23 isn't a guarantee
05/23 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/07 and only about 1 year in 10 sees frost after that.
Whittemore against the rest of the dataset
Whittemore's growing season runs about 127 days, ranking 38,652 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 1,065 of 1,153.
Learn more
Two guides worth reading on 48739: the frost range, on how to read the range around Whittemore's dates instead of trusting one, and local microclimates, on what one yard in Whittemore can differ from the 48739 normal.