Fort Collins, CO 80525 Frost Dates
When can you plant in Fort Collins, CO?
Around 05/03 is the usual last spring frost, about 248 days away. The first fall frost typically arrives around 10/06, about 154 frost-free days later.
The USDA Plant Hardiness Zone Map puts Fort Collins in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 6 weeks of growing season left in Fort Collins before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Fort Collins's last frost
05/03 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 05/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Fort Collins compares
Fort Collins's growing season runs about 154 days, ranking 34,198 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 258 of 624.
Learn more
zone vs. frost date covers why Zone 5b and Fort Collins's frost date answer different questions. the frost range covers how to read the range around Fort Collins's dates instead of trusting one.