Frost dates for Vallecito Reservoir, CO
At Vallecito Reservoir, the median last spring frost (32°F) is May 18 and the median first fall frost is Oct 11, for a typical growing season of 145 days. For a 90% chance that the last frost has passed, wait until Jun 6. Nearby ZIP codes are in USDA hardiness zones 5a to 6b.
- May 18Last spring frost (median)50% chance of 32°F after this date
- Jun 6Safer planting date10% chance of 32°F after this date
- Oct 11First fall frost (median)50% chance of 32°F by this date
- 145 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | May 20 | Jun 5 | Jun 17 |
| 32°F | May 3 | May 18 | Jun 6 |
| 28°F | Apr 20 | May 3 | May 21 |
| 24°F | Apr 7 | Apr 19 | May 3 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Sep 18 | Sep 30 | Oct 15 |
| 32°F | Sep 27 | Oct 11 | Oct 26 |
| 28°F | Oct 8 | Oct 24 | Nov 7 |
| 24°F | Oct 20 | Nov 2 | Nov 15 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 99 days | 118 days | 137 days |
| 32°F | 123 days | 145 days | 167 days |
| 28°F | 151 days | 173 days | 190 days |
| 24°F | 177 days | 196 days | 213 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 81122 | 6a | -10 to -5°F | 10 km |
| 81301 | 6a | -10 to -5°F | 27 km |
| 81137 | 6a | -10 to -5°F | 37 km |
| 81303 | 6b | -5 to 0°F | 38 km |
| 81433 | 5a | -20 to -15°F | 38 km |
| 81121 | 6b | -5 to 0°F | 43 km |
| 81147 | 5b | -15 to -10°F | 45 km |
| 81332 | 5b | -15 to -10°F | 50 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00058590, at 37.3833, -107.5833, elevation 2339 m (7,673 ft).
- Data quality: Estimated from nearby stations (2+ years), 2 years of freeze data.
- Average days per year at or below 32°F: 185.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Vallecito Dam (0 km)
- Lemon Dam (7 km)
- Durango (26 km)
- Durango La Plata Co Airport (31 km)
- Ignacio 6ese (33 km)
- Fort Lewis (45 km)
- Rio Grande Rsvr (47 km)
- Silverton (48 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.