Home › Frost dates › Colorado
Colorado frost dates
Across the 27Colorado weather stations below, the average last spring frost ranges from Apr 24 in La Junta to Jun 21 in Boulder 14 W. The statewide middle is about May 6 for the last spring frost and Oct 8 for the first fall frost. La Junta has the longest growing season, about 174 days. Hardiness zones in these places: 4b, 5a, 5b, 6a, 6b, 7a.
Frost dates by city
| Place | Zone | Last spring frost | 90% safe after | First fall frost | Frost-free days |
|---|---|---|---|---|---|
| La Junta | 6a | Apr 24 | May 6 | Oct 15 | 174 |
| Grand Junction Walker | 7a | Apr 28 | May 14 | Oct 16 | 171 |
| Pueblo | 6a | Apr 30 | May 12 | Oct 9 | 162 |
| Burlington Carson | 6a | May 2 | May 16 | Oct 10 | 161 |
| Dinosaur 2 E | 6a | May 2 | May 17 | Oct 14 | 165 |
| Lamar | 6a | May 2 | May 17 | Oct 7 | 158 |
| Montrose | 6b | May 2 | May 17 | Oct 8 | 159 |
| Colorado Springs | 6a | May 3 | May 15 | Oct 8 | 158 |
| Springfield Comanche | 6b | May 3 | May 17 | Oct 10 | 160 |
| Denver-Stapleton | 6a | May 4 | May 16 | Oct 8 | 157 |
| Trinidad Perry Stokes | 6a | May 4 | May 19 | Oct 9 | 158 |
| Denver | 6a | May 5 | May 19 | Oct 9 | 157 |
| Denver Centennial | 6a | May 5 | May 17 | Oct 8 | 156 |
| Akron Washington | 5b | May 6 | May 19 | Oct 8 | 155 |
| Cortez 8 Se | 7a | May 6 | May 27 | Oct 14 | 161 |
| La Junta 17 Wsw | 6a | May 8 | May 25 | Oct 4 | 149 |
| Rifle Garfield | 6a | May 11 | May 27 | Oct 4 | 146 |
| Nunn 7 Nne | 5a | May 13 | May 27 | Sep 27 | 137 |
| Montrose 11 Ene | 6b | May 20 | Jun 4 | Oct 1 | 134 |
| Limon Wsmo | 5b | May 21 | Jun 4 | Sep 26 | 128 |
| Cortez Montezuma | 7a | May 27 | Jun 11 | Sep 28 | 124 |
| Meeker | 5b | May 30 | Jun 13 | Sep 22 | 115 |
| Aspen Pitkin | 5b | May 31 | Jun 14 | Sep 23 | 115 |
| Durango La Plata | 6b | Jun 1 | Jun 15 | Sep 27 | 118 |
| Craig Moffat | 5b | Jun 6 | Jun 24 | Sep 12 | 98 |
| Alamosa San Luis | 4b | Jun 7 | Jun 24 | Sep 15 | 100 |
| Boulder 14 W | 5b | Jun 21 | Jul 4 | Sep 2 | 73 |
Dates are the 50% probability of a 32°F freeze (NOAA 1991–2020 normals); "90% safe after" is the date after which a later spring freeze happens in only 1 year in 10.
When to plant in Colorado
Using the statewide middle dates (last frost May 6, first frost Oct 8). Adjust for your town with the table above or the planting calendar.
| Plant | When to plant in Colorado |
|---|---|
| Tomatoes | May 13 – May 27 |
| Peas | Mar 25 – Apr 15; fall: Jul 16 – Aug 6 |
| Potatoes | Apr 8 – Apr 29 |
| Green beans | May 13 – May 27; fall: Jul 23 – Aug 6 |
| Garlic | Oct 8 – Nov 5 |
| Tulips | Sep 24 – Nov 5 |