Last spring frost
Apr 24
Frost Dates for Benson, AZ
First fall frost
Oct 31
Growing season
187 days
Hardiness zone
8b
In an average year around Benson, AZ, the last spring frost (32°F) is about Apr 24 and the first fall frost is about Oct 31, giving roughly a 187-day growing season. To be safe most years, wait until Apr 9 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 23 | May 6 | Apr 22 |
| Freeze (32°F) | May 9 | Apr 24 | Apr 9 |
| Hard (28°F) | Apr 28 | Apr 9 | Mar 15 |
| Severe (24°F) | Apr 11 | Mar 13 | Feb 14 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 23 | May 16 | May 12 | May 9 | May 6 | May 3 | Apr 30 | Apr 26 | Apr 22 |
| 32°F | May 9 | May 4 | Apr 30 | Apr 28 | Apr 24 | Apr 21 | Apr 17 | Apr 14 | Apr 9 |
| 28°F | Apr 28 | Apr 21 | Apr 16 | Apr 12 | Apr 9 | Apr 5 | Apr 1 | Mar 27 | Mar 15 |
| 24°F | Apr 11 | Apr 5 | Mar 30 | Mar 19 | Mar 13 | Mar 7 | Mar 2 | Feb 24 | Feb 14 |
| 20°F | Mar 12 | Mar 4 | Feb 27 | Feb 20 | Feb 15 | Feb 8 | Feb 1 | Jan 24 | Jan 11 |
| 16°F | Feb 20 | Feb 10 | Feb 3 | Jan 29 | Jan 21 | Jan 11 | Jan 2 | Dec 26 | Dec 12 |
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 6 | Oct 22 | Nov 5 |
| Freeze (32°F) | Oct 14 | Oct 31 | Nov 15 |
| Hard (28°F) | Oct 21 | Nov 10 | Nov 24 |
| Severe (24°F) | Nov 2 | Nov 21 | Dec 8 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 6 | Oct 11 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 5 |
| 32°F | Oct 14 | Oct 20 | Oct 24 | Oct 28 | Oct 31 | Nov 3 | Nov 6 | Nov 10 | Nov 15 |
| 28°F | Oct 21 | Oct 29 | Nov 3 | Nov 6 | Nov 10 | Nov 14 | Nov 17 | Nov 20 | Nov 24 |
| 24°F | Nov 2 | Nov 8 | Nov 14 | Nov 18 | Nov 21 | Nov 24 | Nov 28 | Dec 2 | Dec 8 |
| 20°F | Nov 13 | Nov 20 | Nov 24 | Nov 28 | Dec 2 | Dec 6 | Dec 10 | Dec 17 | Dec 28 |
| 16°F | Nov 24 | Nov 30 | Dec 4 | Dec 9 | Dec 14 | Dec 21 | Dec 31 | Jan 8 | Jan 24 |
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: Cascabel, Az, about 7.5 miles away@if(!empty($station['elevation_ft'])), at 3,194 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 Benson, AZ?
On average, the last spring frost (32°F) around Benson, AZ is about Apr 24. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 9.
When is the first frost in the fall?
The first fall frost around Benson, 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 24 on average, or Apr 9 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 187 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 85602 Planting calendar → Arizona frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026