When is the last frost in Grant, CO?

For ZIP code 80448, the average last spring frost (32°F) is June 15, based on NOAA 1991-2020 climate normals for the Grant, CO weather station. There is a 1-in-10 chance of a frost after June 30.

When is the first frost in Grant, CO?

The average first fall frost (32°F) is September 9. There is a 1-in-10 chance of frost by August 26, so tender plants are at risk from that point on.

How long is the growing season in 80448?

In half of years, the frost-free season (between the last and first 32°F frost) is at least 84 days long.

Are these frost dates a forecast?

No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.

Frost dates for 80448Grant, CO

The average last spring frost in Grant is June 15 and the average first fall frost is September 9, giving a typical growing season of about 84 days. Dates are based on NOAA 1991-2020 climate normals.

Average last spring frost: Jun 15
Average first fall frost: Sep 9
Growing season: 84 days

Frost risk by date

NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.

Spring dates: chance of a frost AFTER the date. Fall dates: chance of a frost BEFORE the date.
Temperature	Last spring: 90% / 50% / 10% chance	First fall: 10% / 50% / 90% chance	Growing season (50%)	Years with at least one
Light frost (36°F)	—	—	53 days	100%
Frost / freeze (32°F)	Jun 1 · Jun 15 · Jun 30	Aug 26 · Sep 9 · Sep 22	84 days	100%
Hard freeze (28°F)	May 16 · May 30 · Jun 12	Sep 9 · Sep 22 · Oct 4	116 days	100%

Where these dates come from

ZIP code 80448 is matched to the NOAA station Grant, CO, 1.7 km away, at 8,675 ft elevation (393 ft lower than the ZIP code's center). Nearby stations for comparison:

Station	Elevation	Avg last frost	Avg first frost
Grant, CO (used)	8,675 ft	Jun 15	Sep 9
Bailey, CO	7,752 ft	Jun 16	Sep 8
Cabin Creek, CO	10,021 ft	Jun 6	Sep 19
Georgetown, CO	8,520 ft	May 30	Sep 19

Frost dates near Grant

Shawnee, CO 80475 · last Jun 16, first Sep 8
Bailey, CO 80421 · last Jun 15, first Sep 9
Jefferson, CO 80456 · last Jun 15, first Sep 9
Pine, CO 80470 · last Jun 16, first Sep 8
Georgetown, CO 80444 · last May 30, first Sep 19
Silver Plume, CO 80476 · last Jun 6, first Sep 19
Conifer, CO 80433 · last Jun 15, first Sep 9
Dillon, CO 80435 · last —, first —

Frequently asked questions

When is the last frost in Grant, CO?: For ZIP code 80448, the average last spring frost (32°F) is June 15, based on NOAA 1991-2020 climate normals for the Grant, CO weather station. There is a 1-in-10 chance of a frost after June 30.
When is the first frost in Grant, CO?: The average first fall frost (32°F) is September 9. There is a 1-in-10 chance of frost by August 26, so tender plants are at risk from that point on.
How long is the growing season in 80448?: In half of years, the frost-free season (between the last and first 32°F frost) is at least 84 days long.
Are these frost dates a forecast?: No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.