Grover, CO 80611 Frost Dates
80611, near Grover, CO: the frost window
Typically, the last spring freeze lands around 05/12, roughly 257 days out. Fall's first freeze usually shows up around 09/28, roughly 135 days after the last spring frost.
Grover 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
Grover'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.
How much risk comes with planting early here
05/12 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/02 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/25 and only about 1 year in 10 sees frost after that.
Grover against the rest of the dataset
Grover's growing season runs about 135 days, ranking 37,930 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 430 of 624.
Learn more
Two guides worth reading on 80611: local microclimates, on what one yard in Grover can differ from the 80611 normal, and zone vs. frost date, on why Zone 5a and Grover's frost date answer different questions.