Millcreek, UT 84109 Frost Dates
84109, near Millcreek, UT: the frost window
Typically, the last spring freeze lands around 05/07, roughly 252 days out. Fall's first freeze usually shows up around 10/14, roughly 158 days after the last spring frost.
Zone 6b (-5 to 0°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 Millcreek, not a forecast for this year.
Stretching the season past the first frost
Millcreek'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.
Why 05/07 isn't a guarantee
05/07 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 05/27 and only about 1 year in 10 sees frost after that.
Millcreek against the rest of the dataset
Millcreek's growing season runs about 158 days, ranking 32,871 of 40,283 US ZIP codes measured here, longest to shortest. Within UT, it ranks 173 of 344.
Learn more
Two guides worth reading on 84109: zone vs. frost date, on why Zone 6b and Millcreek's frost date answer different questions, and the frost range, on how to read the range around Millcreek's dates instead of trusting one.