Last spring frost
Apr 20
Frost Dates for Prescott Valley, AZ
First fall frost
Oct 27
Growing season
188 days
Hardiness zone
8a
In an average year around Prescott Valley, AZ, the last spring frost (32°F) is about Apr 20 and the first fall frost is about Oct 27, giving roughly a 188-day growing season. To be safe most years, wait until Apr 4 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 21 | May 4 | Apr 20 |
| Freeze (32°F) | May 7 | Apr 20 | Apr 4 |
| Hard (28°F) | Apr 19 | Apr 1 | Mar 11 |
| Severe (24°F) | Apr 2 | Mar 9 | Feb 15 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 21 | May 15 | May 11 | May 7 | May 4 | May 1 | Apr 28 | Apr 25 | Apr 20 |
| 32°F | May 7 | May 1 | Apr 28 | Apr 25 | Apr 20 | Apr 16 | Apr 13 | Apr 8 | Apr 4 |
| 28°F | Apr 19 | Apr 12 | Apr 8 | Apr 5 | Apr 1 | Mar 28 | Mar 23 | Mar 18 | Mar 11 |
| 24°F | Apr 2 | Mar 26 | Mar 19 | Mar 13 | Mar 9 | Mar 4 | Feb 28 | Feb 23 | Feb 15 |
| 20°F | Mar 9 | Mar 2 | Feb 25 | Feb 20 | Feb 15 | Feb 10 | Feb 4 | Jan 30 | Jan 19 |
| 16°F | Feb 21 | Feb 11 | Feb 5 | Jan 31 | Jan 24 | Jan 18 | Jan 10 | Jan 2 | Dec 23 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 3 | Oct 16 | Oct 31 |
| Freeze (32°F) | Oct 13 | Oct 27 | Nov 10 |
| Hard (28°F) | Oct 24 | Nov 8 | Nov 22 |
| Severe (24°F) | Nov 3 | Nov 18 | Dec 3 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 3 | Oct 7 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 31 |
| 32°F | Oct 13 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Oct 31 | Nov 3 | Nov 6 | Nov 10 |
| 28°F | Oct 24 | Oct 29 | Nov 1 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 18 | Nov 22 |
| 24°F | Nov 3 | Nov 8 | Nov 13 | Nov 16 | Nov 18 | Nov 21 | Nov 24 | Nov 28 | Dec 3 |
| 20°F | Nov 16 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 3 | Dec 7 | Dec 11 | Dec 18 |
| 16°F | Nov 25 | Dec 1 | Dec 5 | Dec 9 | Dec 13 | Dec 19 | Dec 24 | Dec 29 | Jan 8 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Prescott Love Fld, Az, about 7.6 miles away@if(!empty($station['elevation_ft'])), at 5,042 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Prescott Valley, AZ?
On average, the last spring frost (32°F) around Prescott Valley, AZ is about Apr 20. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 4.
When is the first frost in the fall?
The first fall frost around Prescott Valley, AZ typically arrives about Oct 27. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Apr 20 on average, or Apr 4 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 188 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 86315 Planting calendar → Arizona frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026