Last spring frost
Mar 28
Frost Dates for Sonoita, AZ
First fall frost
Nov 21
Growing season
237 days
Hardiness zone
8a
In an average year around Sonoita, AZ, the last spring frost (32°F) is about Mar 28 and the first fall frost is about Nov 21, giving roughly a 237-day growing season. To be safe most years, wait until Mar 1 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 4 | Apr 16 | Mar 26 |
| Freeze (32°F) | Apr 21 | Mar 28 | Mar 1 |
| Hard (28°F) | Apr 4 | Mar 1 | Jan 29 |
| Severe (24°F) | Mar 3 | Feb 2 | Dec 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 4 | Apr 29 | Apr 24 | Apr 20 | Apr 16 | Apr 11 | Apr 7 | Apr 3 | Mar 26 |
| 32°F | Apr 21 | Apr 13 | Apr 7 | Apr 2 | Mar 28 | Mar 22 | Mar 17 | Mar 10 | Mar 1 |
| 28°F | Apr 4 | Mar 22 | Mar 13 | Mar 7 | Mar 1 | Feb 25 | Feb 17 | Feb 6 | Jan 29 |
| 24°F | Mar 3 | Feb 23 | Feb 14 | Feb 8 | Feb 2 | Jan 25 | Jan 12 | Jan 5 | Dec 25 |
| 20°F | Feb 22 | Feb 12 | Feb 4 | Jan 29 | Jan 19 | Jan 9 | Jan 2 | Dec 27 | Dec 12 |
| 16°F | Feb 17 | Feb 9 | Feb 4 | Jan 29 | Jan 21 | Jan 8 | Jan 4 | Dec 30 | Dec 19 |
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 25 | Nov 9 | Nov 25 |
| Freeze (32°F) | Nov 5 | Nov 21 | Dec 7 |
| Hard (28°F) | Nov 16 | Dec 2 | Dec 23 |
| Severe (24°F) | Nov 27 | Dec 20 | Jan 26 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 25 | Oct 31 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 16 | Nov 19 | Nov 25 |
| 32°F | Nov 5 | Nov 11 | Nov 15 | Nov 18 | Nov 21 | Nov 24 | Nov 27 | Dec 1 | Dec 7 |
| 28°F | Nov 16 | Nov 22 | Nov 25 | Nov 29 | Dec 2 | Dec 7 | Dec 11 | Dec 16 | Dec 23 |
| 24°F | Nov 27 | Dec 3 | Dec 8 | Dec 14 | Dec 20 | Dec 26 | Jan 1 | Jan 9 | Jan 26 |
| 20°F | Dec 5 | Dec 15 | Dec 23 | Dec 29 | Jan 3 | Jan 9 | Jan 19 | Jan 29 | Feb 12 |
| 16°F | Dec 17 | Dec 27 | Jan 2 | Jan 5 | Jan 14 | Jan 26 | Feb 1 | Feb 7 | Feb 17 |
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: Sonoita, Az, about 3.4 miles away@if(!empty($station['elevation_ft'])), at 4,895 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 Sonoita, AZ?
On average, the last spring frost (32°F) around Sonoita, AZ is about Mar 28. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 1.
When is the first frost in the fall?
The first fall frost around Sonoita, AZ typically arrives about Nov 21. 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 Mar 28 on average, or Mar 1 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 237 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 85637 Planting calendar → Arizona frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026