Frost dates for Denver Intl Airport, CO
At Denver Intl Airport, the median last spring frost (32°F) is May 5 and the median first fall frost is Oct 9, for a typical growing season of 156 days. For a 90% chance that the last frost has passed, wait until May 19. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- May 5Last spring frost (median)50% chance of 32°F after this date
- May 19Safer planting date10% chance of 32°F after this date
- Oct 9First fall frost (median)50% chance of 32°F by this date
- 156 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 3 | May 16 | Jun 2 |
| 32°F | Apr 23 | May 5 | May 19 |
| 28°F | Apr 10 | Apr 25 | May 9 |
| 24°F | Mar 31 | Apr 15 | Apr 30 |
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 19 | Oct 1 | Oct 12 |
| 32°F | Sep 27 | Oct 9 | Oct 20 |
| 28°F | Oct 5 | Oct 18 | Oct 31 |
| 24°F | Oct 13 | Oct 26 | Nov 10 |
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 | 117 days | 136 days | 154 days |
| 32°F | 137 days | 156 days | 173 days |
| 28°F | 155 days | 174 days | 194 days |
| 24°F | 173 days | 193 days | 215 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 80249 | 6a | -10 to -5°F | 4 km |
| 80019 | 6a | -10 to -5°F | 6 km |
| 80603 | 5b | -15 to -10°F | 13 km |
| 80137 | 6a | -10 to -5°F | 14 km |
| 80018 | 6a | -10 to -5°F | 15 km |
| 80102 | 6a | -10 to -5°F | 22 km |
| 80643 | 5b | -15 to -10°F | 34 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 USW00003017, at 39.8328, -104.6575, elevation 1650 m (5,414 ft).
- Data quality: Representative (10+ years), 25 years of freeze data.
- Average days per year at or below 32°F: 156.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Brighton 3 SE (20 km)
- Denver-Stapleton (20 km)
- Cherry Creek Dam (27 km)
- Northglenn (31 km)
- Denver Water Dept (32 km)
- Denver Centennial Airport (33 km)
- Parker (36 km)
- Wheat Ridge 2 (40 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.