Frost dates for Walnut Canyon National Monument, AZ
At Walnut Canyon National Monument, the median last spring frost (32°F) is May 13 and the median first fall frost is Oct 6, for a typical growing season of 145 days. For a 90% chance that the last frost has passed, wait until May 30. Nearby ZIP codes are in USDA hardiness zones 5b to 7a.
- May 13Last spring frost (median)50% chance of 32°F after this date
- May 30Safer planting date10% chance of 32°F after this date
- Oct 6First 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 11 | May 27 | Jun 10 |
| 32°F | Apr 27 | May 13 | May 30 |
| 28°F | Apr 8 | Apr 28 | May 17 |
| 24°F | Mar 18 | Apr 7 | May 1 |
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 17 | Sep 29 | Oct 9 |
| 32°F | Sep 26 | Oct 6 | Oct 21 |
| 28°F | Oct 4 | Oct 18 | Nov 4 |
| 24°F | Oct 14 | Oct 31 | Nov 17 |
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 | 106 days | 124 days | 142 days |
| 32°F | 126 days | 145 days | 166 days |
| 28°F | 147 days | 172 days | 196 days |
| 24°F | 177 days | 205 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% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 86005 | 6a | -10 to -5°F | 14 km |
| 86004 | 6b | -5 to 0°F | 26 km |
| 86015 | 5b | -15 to -10°F | 28 km |
| 86003 | 7a | 0 to 5°F | 29 km |
| 86038 | 6b | -5 to 0°F | 29 km |
| 86017 | 7a | 0 to 5°F | 30 km |
| 86001 | 6a | -10 to -5°F | 31 km |
| 86018 | 6b | -5 to 0°F | 42 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 USC00029156, at 35.1722, -111.5097, elevation 2041 m (6,695 ft).
- Data quality: Representative (10+ years), 13 years of freeze data.
- Average days per year at or below 32°F: 161.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Flagstaff Pulliam Airport (15 km)
- Flagstaff 4 SW (20 km)
- Sunset Crater National Monument (22 km)
- Twin Arrows (23 km)
- Fort Valley (24 km)
- Mund's Park (29 km)
- Bellemont WFO (29 km)
- Oak Creek Canyon (33 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.