Colorado frost dates: Last spring and first autumn frost at every NOAA station, 1991-2020
Across Colorado's 210 NOAA stations with frost dates, the median last spring frost (32°F) runs from April 14 in Grand Junction Weather Office to June 21 in Vail; for half of its places it comes after May 10.
- Typical last spring frost
- May 10median of 115 places
- Typical first autumn frost
- October 4median of 115 places
- Earliest last frost
- April 14Grand Junction Weather Office
- Latest last frost
- June 21Vail
When is the last frost in Colorado, town by town?
Each date is NOAA's: "after May 10 in half of years" means the last 32°F night of spring came after May 10 in half of the years 1991-2020. By the 1-in-10 date, the last frost has passed in nine years out of ten.
Find your town in the list, or look up a ZIP code for the stations nearest it.
| Place or station | Last frost (median) | 1 in 10 after | First frost (median) | 1 in 10 before | Growing season | Zone |
|---|---|---|---|---|---|---|
| Grand Junction Weather Office | April 14 | April 28 | October 23 | October 11 | 190 days | – |
| Palisade | April 17 | May 3 | October 26 | October 12 | 190 days | 7b |
| Gateway (1 mi ENE) | April 20 | May 5 | October 21 | October 7 | 182 days | 7a |
| Grand Junction (6 mi ESE) | April 23 | May 9 | October 20 | October 5 | 179 days | 7a |
| John Martin Dam | April 24 | May 8 | October 15 | October 2 | 172 days | 6a |
| Kim (10 mi SSE) | April 24 | May 6 | October 18 | October 4 | 175 days | 6b |
| La JuntaLa Junta Municipal Airport | April 24 | May 6 | October 15 | October 3 | 173 days | 6a |
| Colorado National Monument | April 26 | May 15 | October 16 | October 1 | 172 days | 7a |
| La Junta station | April 26 | May 9 | October 15 | October 3 | 171 days | – |
| Pueblo Reservoir | April 26 | May 8 | October 13 | September 30 | 166 days | 6a |
| Uravan | April 26 | May 8 | October 18 | October 6 | 174 days | 7a |
| Fruita | April 27 | May 7 | October 11 | September 28 | 164 days | – |
| La Junta (20 mi S) | April 27 | May 11 | October 14 | October 2 | 168 days | – |
| Sheridan Lake | April 27 | May 10 | October 15 | October 2 | 170 days | – |
| Grand JunctionGrand Junction Walker Field | April 28 | May 14 | October 16 | October 3 | 171 days | 6b |
| Montrose #2 | April 28 | May 12 | October 14 | October 1 | 167 days | – |
| Sheridan Lake (4 mi E) | April 28 | May 12 | October 13 | October 1 | 167 days | – |
| Campo7 mi S | April 29 | May 12 | October 13 | October 1 | 166 days | 6b |
| Las Animas | April 29 | May 11 | October 12 | October 2 | 166 days | 6a |
| Cheraw1 mi N | April 30 | May 13 | October 10 | October 1 | 163 days | 6a |
| Denver Water Dept | April 30 | May 13 | October 12 | September 28 | 165 days | 6b |
| Eads | April 30 | May 12 | October 13 | October 1 | 165 days | 6a |
| Lamar station | April 30 | May 13 | October 10 | October 1 | 163 days | 6a |
| PuebloPueblo Memorial Airport | April 30 | May 12 | October 9 | September 27 | 161 days | 5b |
| Sterling | April 30 | May 12 | October 9 | September 28 | 161 days | – |
| Trinidad station | April 30 | May 11 | October 15 | October 1 | 167 days | 6a |
| Walsh1 mi W | April 30 | May 12 | October 14 | October 1 | 166 days | 6b |
| Weather Office Pueblo | April 30 | May 12 | October 9 | September 28 | 162 days | – |
| Cheyenne Wells2 mi NE | May 1 | May 17 | October 14 | October 1 | 165 days | 6a |
| Delta3 mi E | May 1 | May 14 | October 7 | September 26 | 159 days | – |
| Holly | May 1 | May 14 | October 12 | September 29 | 163 days | 6a |
| Rocky Ford2 mi SE | May 1 | May 14 | October 8 | September 26 | 159 days | 5b |
| Shoshone | May 1 | May 14 | October 14 | October 1 | 164 days | – |
| Yuma | May 1 | May 13 | October 12 | September 30 | 164 days | 6a |
| BurlingtonBurlington Carson Airport | May 2 | May 16 | October 10 | September 27 | 160 days | 6a |
| Dinosaur2 mi E | May 2 | May 17 | October 14 | September 30 | 161 days | – |
| Fort Collins | May 2 | May 14 | October 7 | September 24 | 157 days | 6a |
| GreeleyGreeley Unc | May 2 | May 14 | October 8 | September 26 | 159 days | 6a |
| LamarLamar Municipal Airport | May 2 | May 17 | October 7 | September 28 | 157 days | 6a |
| Marston Filter Plant | May 2 | May 17 | October 11 | September 27 | 160 days | 6a |
| MontroseMontrose Regional Airport | May 2 | May 17 | October 8 | September 26 | 157 days | 6a |
| Northglenn | May 2 | May 14 | October 11 | September 26 | 160 days | 6a |
| Ordway1 mi ENE | May 2 | May 14 | October 8 | September 25 | 159 days | – |
| Brighton3 mi SE | May 3 | May 16 | October 7 | September 26 | 155 days | 5b |
| Cedaredge3 mi E | May 3 | May 21 | October 9 | September 27 | 156 days | 6b |
| Colorado SpringsColorado Springs Municipal Airport | May 3 | May 15 | October 8 | September 26 | 158 days | 6a |
| Fort Collins (4 mi E) | May 3 | May 15 | October 6 | September 22 | 154 days | – |
| Joes | May 3 | May 15 | October 9 | September 29 | 158 days | 5b |
| Lakewood | May 3 | May 18 | October 7 | September 24 | 155 days | 6a |
| Ordway (21 mi N) | May 3 | May 16 | October 7 | September 27 | 155 days | – |
| Paonia1 mi SW | May 3 | May 18 | October 12 | September 27 | 159 days | 6b |
| Ralston Reservoir | May 3 | May 17 | October 14 | September 30 | 161 days | 6a |
| SpringfieldSpringfield Comanche | May 3 | May 17 | October 10 | September 29 | 158 days | 6a |
| Cañon CityCanon City | May 4 | May 18 | October 7 | September 25 | 153 days | 6a |
| Denver-Stapleton | May 4 | May 16 | October 8 | September 25 | 156 days | 6a |
| Fleming3 mi SW | May 4 | May 16 | October 11 | September 29 | 157 days | 5b |
| Idalia | May 4 | May 17 | October 9 | September 24 | 155 days | – |
| Seibert | May 4 | May 17 | October 11 | September 25 | 158 days | – |
| TrinidadTrinidad Perry Stokes Airport | May 4 | May 19 | October 9 | September 28 | 156 days | 6a |
| Wild Horse (6 mi N) | May 4 | May 17 | October 8 | September 26 | 155 days | – |
| Arapahoe (12 mi S) | May 5 | May 19 | October 9 | September 28 | 156 days | – |
| Bonny Dam (2 mi NE) | May 5 | May 19 | October 10 | September 28 | 155 days | 6a |
| CentennialDenver Centennial Airport | May 5 | May 17 | October 8 | September 25 | 154 days | 6a |
| DenverDenver International Airport | May 5 | May 19 | October 9 | September 27 | 156 days | 5b |
| Flagler1 mi S | May 5 | May 20 | October 8 | September 27 | 155 days | – |
| Kim (15 mi NNE) | May 5 | May 19 | October 9 | September 27 | 156 days | – |
| Rye1 mi SW | May 5 | May 20 | October 10 | September 27 | 156 days | 6b |
| Tacony (13 mi SE) | May 5 | May 16 | October 6 | September 26 | 153 days | 6a |
| Wheat RidgeWheat Ridge 2 | May 5 | May 18 | October 5 | September 20 | 151 days | 6a |
| AkronAkron Washington County Airport | May 6 | May 19 | October 8 | September 27 | 155 days | 5b |
| Boulder | May 6 | May 18 | October 5 | September 21 | 151 days | – |
| Burlington station | May 6 | May 19 | October 9 | September 27 | 155 days | 6a |
| Cortez (8 mi SE) | May 6 | May 27 | October 14 | September 30 | 158 days | 7a |
| Ellicott7 mi S | May 6 | May 28 | October 3 | September 21 | 149 days | – |
| Fort Morgan | May 6 | May 19 | October 6 | September 24 | 153 days | – |
| Sedgwick5 mi S | May 6 | May 18 | October 7 | September 24 | 152 days | 5b |
| Stratton | May 6 | May 17 | October 9 | September 26 | 155 days | – |
| Walsenburg1 mi NW | May 6 | May 20 | October 4 | September 23 | 149 days | 6a |
| Cherry CreekCherry Creek Dam | May 7 | May 21 | October 8 | September 25 | 152 days | – |
| Julesburg | May 7 | May 18 | October 6 | September 23 | 152 days | – |
| Kit Carson (9 mi NNE) | May 7 | May 24 | October 6 | September 25 | 151 days | – |
| Longmont2 mi ESE | May 7 | May 22 | October 5 | September 23 | 151 days | – |
| Wray | May 7 | May 19 | October 6 | September 25 | 151 days | 5b |
| Akron (4 mi E) | May 8 | May 22 | October 6 | September 25 | 149 days | 5b |
| Genoa | May 8 | May 22 | October 10 | September 28 | 155 days | – |
| Kassler | May 8 | May 22 | October 3 | September 21 | 147 days | 5b |
| La Junta (17 mi WSW) | May 8 | May 25 | October 4 | September 24 | 148 days | 5b |
| Arapahoe (14 mi N) | May 9 | May 22 | October 7 | September 23 | 150 days | – |
| Castle Rock | May 9 | May 24 | October 2 | September 17 | 143 days | 5b |
| Cumbre Vista - Colorado Springs 1 | May 9 | May 20 | October 6 | September 27 | 150 days | – |
| Karval | May 9 | May 23 | October 6 | September 25 | 149 days | 6a |
| Mesa Verde National Park | May 9 | May 27 | October 14 | October 1 | 156 days | 7a |
| New Raymer | May 9 | May 22 | October 4 | September 21 | 146 days | – |
| Parker | May 9 | May 23 | October 3 | September 21 | 145 days | – |
| Rush (1 mi N) | May 9 | May 22 | October 4 | September 21 | 146 days | 6a |
| Hugo1 mi NW | May 10 | May 25 | October 2 | September 21 | 143 days | – |
| Kit Carson | May 10 | May 24 | October 1 | September 20 | 142 days | 5b |
| Leroy (5 mi WSW) | May 10 | May 22 | October 6 | September 22 | 147 days | 5b |
| Loveland2 mi N | May 10 | May 22 | October 1 | September 15 | 142 days | 5b |
| Massadona (3 mi E) | May 10 | May 27 | October 4 | September 20 | 147 days | – |
| Black Forest6 mi WNW | May 11 | May 25 | October 6 | September 25 | 147 days | 6a |
| Crook | May 11 | May 23 | October 4 | September 23 | 145 days | 5b |
| Dove Creek | May 11 | May 25 | October 12 | September 29 | 152 days | – |
| Holyoke | May 11 | May 23 | October 3 | September 20 | 144 days | 5b |
| Paradox (2 mi N) | May 11 | May 29 | October 5 | September 23 | 146 days | 6b |
| RifleRifle Garfield County Airport | May 11 | May 27 | October 4 | September 23 | 143 days | 5b |
| Trinidad Lake | May 11 | May 25 | October 4 | September 22 | 145 days | 6a |
| Briggsdale | May 12 | May 25 | September 28 | September 15 | 135 days | 5a |
| Cortez station | May 12 | May 31 | October 7 | September 26 | 147 days | – |
| Dinosaur National Monument | May 12 | June 1 | October 5 | September 23 | 146 days | 6a |
| Matheson8 mi SE | May 12 | May 26 | October 2 | September 19 | 141 days | – |
| Shaw (4 mi ENE) | May 12 | May 26 | October 4 | September 21 | 143 days | – |
| Waterdale | May 12 | May 30 | October 1 | September 18 | 141 days | 5b |
| Byers5 mi ENE | May 13 | May 30 | October 2 | September 20 | 142 days | 5a |
| Glenwood SpringsGlenwood Springs #2 | May 13 | May 30 | October 3 | September 20 | 142 days | 6a |
| Nunn7 mi NNE | May 13 | May 27 | September 27 | September 14 | 136 days | 5a |
| Monument station | May 14 | May 31 | October 1 | September 16 | 138 days | – |
| Lindon (5 mi WNW) | May 15 | May 30 | October 2 | September 20 | 139 days | 5b |
| Rangely1 mi E | May 15 | June 2 | October 1 | September 19 | 136 days | 5b |
| Woodrow (6 mi NNE) | May 15 | May 28 | October 1 | September 21 | 140 days | 4b |
| Yellow Jacket (4 mi NE) | May 15 | May 31 | October 8 | September 26 | 147 days | – |
| Elizabeth2 mi NW | May 16 | June 1 | October 2 | September 18 | 137 days | – |
| Roxborough State Park | May 16 | June 1 | October 1 | September 17 | 136 days | – |
| Saguache | May 16 | May 31 | September 28 | September 18 | 135 days | – |
| Strontia Springs Dam | May 16 | June 6 | September 29 | September 16 | 132 days | 5b |
| Cheesman | May 17 | June 6 | October 1 | September 19 | 135 days | 5b |
| Collbran1 mi WSW | May 17 | June 3 | September 30 | September 18 | 136 days | 5b |
| Monument3 mi S | May 17 | May 30 | October 1 | September 19 | 136 days | – |
| Ouray station | May 17 | June 3 | October 1 | September 19 | 137 days | 6b |
| Yellow Jacket (2 mi W) | May 17 | June 4 | October 9 | September 24 | 145 days | 6b |
| New Raymer (21 mi N) | May 18 | June 2 | September 29 | September 15 | 133 days | – |
| OurayOuray #2 | May 18 | May 31 | October 4 | September 24 | 139 days | – |
| Vallecito Reservoir | May 18 | June 6 | October 11 | September 27 | 145 days | – |
| Guffey9 mi SE | May 19 | May 31 | October 2 | September 19 | 134 days | – |
| Montrose (11 mi ENE) | May 20 | June 4 | October 1 | September 19 | 132 days | 6a |
| Buckhorn Mountain (1 mi E) | May 21 | June 4 | September 29 | September 12 | 128 days | 5b |
| Durango station | May 21 | June 7 | October 2 | September 19 | 134 days | 6b |
| Glade Park (17 mi W) | May 21 | June 9 | September 26 | September 14 | 126 days | 6a |
| Great Sand Dunes National Park & Preserve | May 21 | June 3 | October 1 | September 19 | 131 days | 6a |
| LimonLimon Wsmo | May 21 | June 4 | September 26 | September 14 | 127 days | 5b |
| Norwood #2 | May 21 | June 5 | October 1 | September 19 | 131 days | – |
| Black Canyon Of The Gunnison | May 23 | June 9 | October 1 | September 20 | 130 days | 5b |
| Del Norte3 mi ENE | May 23 | June 8 | September 25 | September 13 | 123 days | 5b |
| Evergreen | May 23 | June 10 | September 22 | September 6 | 118 days | 5b |
| Ignacio6 mi ESE | May 23 | June 7 | September 29 | September 18 | 128 days | 6a |
| Rifle (3 mi ENE) | May 23 | June 6 | September 25 | September 13 | 124 days | – |
| Center4 mi SSW | May 24 | June 8 | September 24 | September 12 | 120 days | 5a |
| Gross Reservoir | May 24 | June 10 | September 23 | September 9 | 120 days | 5b |
| Altenbern | May 25 | June 13 | September 25 | September 10 | 120 days | 6a |
| Blanca4 mi NW | May 25 | June 12 | September 22 | September 10 | 117 days | 5b |
| Norwood | May 25 | June 13 | October 1 | September 14 | 128 days | 6a |
| Crestone2 mi SE | May 26 | June 9 | September 26 | September 14 | 120 days | 6a |
| Cripple Creek3 mi NNW | May 26 | June 9 | September 26 | September 13 | 121 days | – |
| Placerville | May 26 | June 6 | September 29 | September 17 | 125 days | – |
| Buena Vista2 mi S | May 27 | June 11 | September 23 | September 10 | 116 days | 5b |
| CortezCortez Montezuma County Airport | May 27 | June 11 | September 28 | September 17 | 125 days | 6a |
| Sheep Mountain | May 27 | June 10 | September 25 | September 11 | 119 days | 6a |
| Lemon Dam | May 28 | June 10 | September 30 | September 15 | 122 days | 5b |
| Manassa | May 28 | June 11 | September 21 | September 9 | 115 days | 5a |
| Craig (4 mi SW) | May 29 | June 13 | September 20 | September 5 | 113 days | 5a |
| Eastonville (2 mi NNW) | May 29 | June 13 | September 21 | September 9 | 114 days | – |
| Salida | May 29 | June 12 | September 20 | September 8 | 112 days | – |
| Alamosa (1 mi E) | May 30 | June 13 | September 17 | September 4 | 108 days | – |
| Estes Park3 mi SSE | May 30 | June 14 | September 17 | September 3 | 109 days | 5b |
| Georgetown | May 30 | June 14 | September 19 | September 5 | 112 days | 5b |
| MeekerMeeker Airport | May 30 | June 13 | September 22 | September 10 | 117 days | 4b |
| AspenAspen Pitkin County Airport | May 31 | June 14 | September 23 | September 11 | 114 days | 5b |
| San Luis1 mi S | May 31 | June 14 | September 23 | September 10 | 115 days | – |
| Vallecito Dam | May 31 | June 14 | September 26 | September 14 | 119 days | 5b |
| Virginia Dale (7 mi ENE) | May 31 | June 15 | September 19 | September 5 | 110 days | 5a |
| Divide4 mi NW | June 1 | June 17 | September 21 | September 7 | 110 days | – |
| DurangoDurango La Plata County Airport | June 1 | June 15 | September 27 | September 15 | 116 days | 5b |
| Fort Lewis | June 1 | June 19 | September 27 | September 13 | 116 days | – |
| Hayden | June 1 | June 16 | September 20 | September 7 | 109 days | 5a |
| Aspen (1 mi SW) | June 2 | June 17 | September 23 | September 12 | 113 days | 5b |
| Lake George (8 mi SW) | June 2 | June 17 | September 19 | September 6 | 108 days | 4b |
| Northdale | June 3 | June 19 | September 25 | September 12 | 113 days | 5b |
| Ruxton Park | June 3 | June 23 | September 17 | August 30 | 102 days | 5b |
| Mancos1 mi SW | June 4 | June 19 | September 24 | September 9 | 111 days | 6a |
| Meeker station | June 4 | June 23 | September 16 | September 3 | 104 days | – |
| Coal CreekCoal Creek Canyon | June 5 | June 19 | September 16 | September 2 | 103 days | 5b |
| Rustic (9 mi WSW) | June 5 | June 20 | September 16 | September 5 | 101 days | 5b |
| Cabin Creek | June 6 | June 21 | September 19 | September 5 | 103 days | 5b |
| CraigCraig Moffat County Airport | June 6 | June 24 | September 12 | August 31 | 96 days | 4a |
| Green Mount Dam | June 6 | June 23 | September 14 | August 31 | 98 days | – |
| Waverly (1 mi W) | June 6 | June 22 | September 15 | September 3 | 100 days | 4a |
| AlamosaAlamosa-Bergman Field | June 7 | June 24 | September 15 | September 4 | 98 days | 4b |
| Lake City | June 8 | June 24 | September 17 | September 6 | 101 days | 5a |
| Blue Mesa Lake | June 9 | June 24 | September 16 | September 3 | 96 days | 5a |
| Lake City (1 mi NNE) | June 9 | June 22 | September 17 | September 5 | 99 days | – |
| Steamboat Springs | June 9 | June 24 | September 12 | August 31 | 93 days | 4b |
| Monte Vista2 mi W | June 11 | June 25 | September 13 | September 1 | 92 days | 4b |
| Ridgway | June 11 | June 30 | September 13 | September 1 | 92 days | 5a |
| Westcliffe | June 11 | June 28 | September 9 | August 28 | 89 days | 4b |
| Williams Fork Dam | June 12 | June 25 | September 10 | August 31 | 89 days | 4b |
| Grand Lake (6 mi SSW) | June 13 | June 28 | September 7 | August 21 | 84 days | – |
| Allenspark3 mi NW | June 14 | June 28 | September 12 | August 25 | 92 days | – |
| Kremmling | June 14 | June 30 | September 5 | August 26 | 80 days | 4a |
| Yampa | June 14 | June 28 | September 11 | August 29 | 89 days | 5a |
| Grant | June 15 | June 30 | September 9 | August 26 | 84 days | 5b |
| Rio Grande Reservoir | June 15 | June 30 | September 11 | August 27 | 85 days | – |
| Bailey | June 16 | July 1 | September 8 | August 27 | 84 days | 5a |
| FairplayFairplay S Park Rd | June 16 | June 30 | September 9 | August 21 | 83 days | – |
| Maybell | June 16 | July 1 | September 9 | August 26 | 83 days | 4a |
| Twin LakesTwin Lakes Reservoir | June 16 | June 29 | September 10 | August 24 | 85 days | 5a |
| Cimarron | June 20 | July 7 | September 10 | August 23 | 81 days | 4b |
| Taylor Park | June 20 | July 2 | September 8 | August 25 | 80 days | 3a |
| Boulder (14 mi W) | June 21 | July 4 | September 2 | August 17 | 71 days | 5a |
| Cochetopa Creek | June 21 | July 7 | September 5 | August 21 | 74 days | 4b |
| Vail | June 21 | July 9 | September 7 | August 26 | 77 days | 5b |
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities, growing-season length); station daily lows via ACIS (zone). Growing season: NOAA's median number of days between the last spring and first autumn 32°F night. Zone: the USDA's plant hardiness rule applied to the station's own 1991-2020 coldest nights.