Last spring frost
Apr 9
Frost Dates for Willcox, AZ
First fall frost
Oct 31
Growing season
204 days
Hardiness zone
8b
In an average year around Willcox, AZ, the last spring frost (32°F) is about Apr 9 and the first fall frost is about Oct 31, giving roughly a 204-day growing season. To be safe most years, wait until Mar 20 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 10 | Apr 26 | Apr 9 |
| Freeze (32°F) | Apr 29 | Apr 9 | Mar 20 |
| Hard (28°F) | Apr 10 | Mar 16 | Feb 24 |
| Severe (24°F) | Mar 13 | Feb 24 | Jan 30 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 10 | May 5 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 19 | Apr 15 | Apr 9 |
| 32°F | Apr 29 | Apr 21 | Apr 16 | Apr 12 | Apr 9 | Apr 5 | Mar 31 | Mar 28 | Mar 20 |
| 28°F | Apr 10 | Apr 2 | Mar 27 | Mar 21 | Mar 16 | Mar 13 | Mar 8 | Mar 3 | Feb 24 |
| 24°F | Mar 13 | Mar 8 | Mar 3 | Feb 28 | Feb 24 | Feb 18 | Feb 12 | Feb 6 | Jan 30 |
| 20°F | Feb 26 | Feb 18 | Feb 11 | Feb 6 | Feb 1 | Jan 29 | Jan 23 | Jan 16 | Jan 5 |
| 16°F | Feb 10 | Feb 1 | Jan 28 | Jan 22 | Jan 17 | Jan 11 | Jan 3 | Dec 27 | Dec 14 |
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 11 | Oct 22 | Nov 3 |
| Freeze (32°F) | Oct 20 | Oct 31 | Nov 14 |
| Hard (28°F) | Oct 28 | Nov 12 | Nov 26 |
| Severe (24°F) | Nov 8 | Nov 25 | Dec 11 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 11 | Oct 15 | Oct 18 | Oct 20 | Oct 22 | Oct 24 | Oct 27 | Oct 29 | Nov 3 |
| 32°F | Oct 20 | Oct 23 | Oct 26 | Oct 29 | Oct 31 | Nov 3 | Nov 6 | Nov 10 | Nov 14 |
| 28°F | Oct 28 | Nov 1 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 22 | Nov 26 |
| 24°F | Nov 8 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 5 | Dec 11 |
| 20°F | Nov 21 | Nov 26 | Nov 30 | Dec 4 | Dec 8 | Dec 13 | Dec 19 | Dec 25 | Jan 3 |
| 16°F | Dec 1 | Dec 8 | Dec 15 | Dec 23 | Dec 29 | Jan 3 | Jan 9 | Jan 16 | Jan 27 |
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: Willcox, Az, about 17.1 miles away@if(!empty($station['elevation_ft'])), at 4,170 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 Willcox, AZ?
On average, the last spring frost (32°F) around Willcox, AZ is about Apr 9. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 20.
When is the first frost in the fall?
The first fall frost around Willcox, AZ typically arrives about Oct 31. 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 9 on average, or Mar 20 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 204 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 85643 Planting calendar → Arizona frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026