Frost Dates & Planting Calendars in Colorado
Typical last spring frost, first fall frost, and growing-season length for 68 cities in Colorado, based on NOAA 1991–2020 climate normals. Click a city for its full frost-date summary, monthly temperature chart, and 42-crop planting calendar.
| City | Last Spring Frost (typical) | First Fall Frost (typical) | Growing Season | USDA Zone |
|---|---|---|---|---|
| Denver | April 30 | October 12 | 165 days | 6a |
| Colorado Springs | May 3 | October 8 | 158 days | 6a |
| Aurora | May 4 | October 8 | 156 days | 6a |
| Fort Collins | May 2 | October 7 | 157 days | 5b |
| Lakewood | May 3 | October 7 | 155 days | 6a |
| Thornton | May 2 | October 11 | 160 days | 6a |
| Westminster | May 2 | October 11 | 160 days | 6a |
| Arvada | May 5 | October 5 | 151 days | 6a |
| Centennial | May 5 | October 8 | 154 days | 6a |
| Pueblo | April 30 | October 9 | 162 days | 6a |
| Greeley | May 2 | October 8 | 159 days | 5a |
| Boulder | May 6 | October 5 | 151 days | 6a |
| Highlands Ranch | May 5 | October 8 | 154 days | 6a |
| Longmont | May 7 | October 5 | 151 days | 5b |
| Loveland | May 10 | October 1 | 142 days | 5b |
| Broomfield | May 2 | October 11 | 160 days | 6a |
| Grand Junction | April 14 | October 23 | 190 days | 7a |
| Castle Rock | May 9 | October 2 | 143 days | 5b |
| Commerce City | May 4 | October 8 | 156 days | 6a |
| Parker | May 9 | October 3 | 145 days | 5b |
| Littleton | May 2 | October 11 | 160 days | 6a |
| Southglenn | May 5 | October 8 | 154 days | 6a |
| Northglenn | May 2 | October 11 | 160 days | 6a |
| Brighton | May 3 | October 7 | 155 days | 5b |
| Dakota Ridge | May 2 | October 11 | 160 days | 5b |
| Englewood | May 2 | October 11 | 160 days | 6a |
| Security-Widefield | May 3 | October 8 | 158 days | 6a |
| Windsor | May 3 | October 6 | 154 days | 5b |
| Ken Caryl | May 2 | October 11 | 160 days | 6a |
| Wheat Ridge | May 5 | October 5 | 151 days | 6a |
| Pueblo West | April 26 | October 13 | 166 days | 6a |
| Fountain | May 3 | October 8 | 158 days | 6a |
| Lafayette | May 2 | October 11 | 160 days | 6a |
| Castlewood | May 5 | October 8 | 154 days | 6a |
| Columbine | May 2 | October 11 | 160 days | 6a |
| Erie | May 7 | October 5 | 151 days | 5b |
| Evans | May 2 | October 8 | 159 days | 5b |
| Louisville | May 6 | October 5 | 151 days | 6a |
| Golden | May 3 | October 14 | 161 days | 5b |
| Clifton | April 23 | October 20 | 179 days | 7a |
| Montrose | April 28 | October 14 | 167 days | 6b |
| Sherrelwood | May 2 | October 11 | 160 days | 6a |
| Durango | May 21 | October 2 | 134 days | 6a |
| Canon City | May 4 | October 7 | 153 days | 6a |
| Cimarron Hills | May 3 | October 8 | 158 days | 6a |
| Greenwood Village | May 2 | October 11 | 160 days | 6a |
| Johnstown | May 10 | October 1 | 142 days | 5b |
| Welby | May 2 | October 11 | 160 days | 6a |
| Sterling | April 30 | October 9 | 161 days | 5b |
| Fort Carson | May 3 | October 8 | 158 days | 6a |
| Lone Tree | May 5 | October 8 | 154 days | 6a |
| Black Forest | May 9 | October 6 | 150 days | 5b |
| Superior | May 6 | October 5 | 151 days | 6a |
| Fruita | April 27 | October 11 | 164 days | 7a |
| Steamboat Springs | June 9 | September 12 | 93 days | 5b |
| Federal Heights | May 2 | October 11 | 160 days | 6a |
| Firestone | May 7 | October 5 | 151 days | 5b |
| Frederick | May 7 | October 5 | 151 days | 5b |
| Fort Morgan | May 6 | October 6 | 153 days | 5b |
| Berkley | May 5 | October 5 | 151 days | 6a |
| Cherry Creek | May 7 | October 8 | 152 days | 6a |
| The Pinery | May 9 | October 3 | 145 days | 5b |
| Castle Pines North | May 9 | October 2 | 143 days | 5b |
| Edwards | June 21 | September 7 | 77 days | 5b |
| Glenwood Springs | May 13 | October 3 | 142 days | 6a |
| Alamosa | May 30 | September 17 | 108 days | 4b |
| Rifle | May 11 | October 4 | 143 days | 6a |
| Gunbarrel | May 6 | October 5 | 151 days | 6a |