Frost dates for Denver Water Dept, CO
At Denver Water Dept, the median last spring frost (32°F) is Apr 30 and the median first fall frost is Oct 12, for a typical growing season of 165 days. For a 90% chance that the last frost has passed, wait until May 13. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 30Last spring frost (median)50% chance of 32°F after this date
- May 13Safer planting date10% chance of 32°F after this date
- Oct 12First fall frost (median)50% chance of 32°F by this date
- 165 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 | Apr 27 | May 8 | May 25 |
| 32°F | Apr 15 | Apr 30 | May 13 |
| 28°F | Apr 1 | Apr 18 | May 5 |
| 24°F | Mar 13 | Apr 4 | Apr 24 |
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 21 | Oct 4 | Oct 16 |
| 32°F | Sep 28 | Oct 12 | Oct 26 |
| 28°F | Oct 5 | Oct 21 | Nov 5 |
| 24°F | Oct 14 | Oct 31 | Nov 14 |
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 | 128 days | 147 days | 166 days |
| 32°F | 145 days | 165 days | 184 days |
| 28°F | 163 days | 184 days | 206 days |
| 24°F | 182 days | 206 days | 232 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 |
|---|---|---|---|
| 80204 | 6a | -10 to -5°F | 1 km |
| 80203 | 6a | -10 to -5°F | 2 km |
| 80290 | 6a | -10 to -5°F | 2 km |
| 80202 | 6a | -10 to -5°F | 3 km |
| 80218 | 6a | -10 to -5°F | 3 km |
| 80223 | 6a | -10 to -5°F | 4 km |
| 80211 | 6a | -10 to -5°F | 4 km |
| 80209 | 6a | -10 to -5°F | 4 km |
| 80219 | 6a | -10 to -5°F | 4 km |
| 80206 | 6a | -10 to -5°F | 5 km |
| 80205 | 6a | -10 to -5°F | 5 km |
| 80212 | 6a | -10 to -5°F | 6 km |
| 80210 | 6a | -10 to -5°F | 7 km |
| 80246 | 6a | -10 to -5°F | 7 km |
| 80216 | 6a | -10 to -5°F | 8 km |
| 80222 | 6a | -10 to -5°F | 9 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 USC00052223, at 39.7294, -105.0083, elevation 1594 m (5,228 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 150.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Lakewood (10 km)
- Wheat Ridge 2 (11 km)
- Denver-Stapleton (12 km)
- Marston Fltr Plant (13 km)
- Northglenn (19 km)
- Cherry Creek Dam (19 km)
- Denver Centennial Airport (22 km)
- Ralston Rsvr (22 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.