Last spring frost
Mar 18
Frost Dates for Douglas, AZ
First fall frost
Nov 13
Growing season
235 days
Hardiness zone
8a
In an average year around Douglas, AZ, the last spring frost (32°F) is about Mar 18 and the first fall frost is about Nov 13, giving roughly a 235-day growing season. To be safe most years, wait until Feb 27 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) | Apr 27 | Apr 7 | Mar 18 |
| Freeze (32°F) | Apr 12 | Mar 18 | Feb 27 |
| Hard (28°F) | Mar 24 | Feb 27 | Jan 31 |
| Severe (24°F) | Mar 3 | Feb 3 | Jan 5 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 27 | Apr 21 | Apr 16 | Apr 11 | Apr 7 | Apr 5 | Mar 31 | Mar 27 | Mar 18 |
| 32°F | Apr 12 | Apr 5 | Mar 31 | Mar 25 | Mar 18 | Mar 14 | Mar 10 | Mar 4 | Feb 27 |
| 28°F | Mar 24 | Mar 12 | Mar 6 | Mar 2 | Feb 27 | Feb 22 | Feb 16 | Feb 9 | Jan 31 |
| 24°F | Mar 3 | Feb 23 | Feb 15 | Feb 8 | Feb 3 | Jan 31 | Jan 25 | Jan 17 | Jan 5 |
| 20°F | Feb 13 | Feb 3 | Jan 26 | Jan 18 | Jan 11 | Jan 6 | Jan 1 | Dec 25 | Dec 14 |
| 16°F | Feb 6 | Jan 24 | Jan 11 | Jan 7 | Jan 3 | Dec 29 | Dec 24 | Dec 17 | Dec 9 |
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 20 | Nov 3 | Nov 19 |
| Freeze (32°F) | Oct 27 | Nov 13 | Nov 30 |
| Hard (28°F) | Nov 5 | Nov 25 | Dec 9 |
| Severe (24°F) | Nov 15 | Dec 6 | Dec 23 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 20 | Oct 25 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 9 | Nov 13 | Nov 19 |
| 32°F | Oct 27 | Nov 1 | Nov 5 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 24 | Nov 30 |
| 28°F | Nov 5 | Nov 12 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 5 | Dec 9 |
| 24°F | Nov 15 | Nov 25 | Nov 30 | Dec 3 | Dec 6 | Dec 8 | Dec 12 | Dec 18 | Dec 23 |
| 20°F | Nov 28 | Dec 4 | Dec 9 | Dec 15 | Dec 18 | Dec 22 | Dec 27 | Jan 3 | Jan 12 |
| 16°F | Dec 3 | Dec 14 | Dec 18 | Dec 23 | Dec 27 | Jan 1 | Jan 6 | Jan 11 | Jan 29 |
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: Douglas, Az, about 15.6 miles away@if(!empty($station['elevation_ft'])), at 4,040 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 Douglas, AZ?
On average, the last spring frost (32°F) around Douglas, AZ is about Mar 18. In cooler years it can run later, so for a safer bet many gardeners wait until Feb 27.
When is the first frost in the fall?
The first fall frost around Douglas, AZ typically arrives about Nov 13. 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 18 on average, or Feb 27 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 235 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 85607 Planting calendar → Arizona frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026