Last spring frost
Feb 23
Frost Dates for Maricopa, AZ
First fall frost
Nov 24
Growing season
274 days
Hardiness zone
9a
In an average year around Maricopa, AZ, the last spring frost (32°F) is about Feb 23 and the first fall frost is about Nov 24, giving roughly a 274-day growing season. To be safe most years, wait until Jan 29 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 10 | Mar 12 | Feb 24 |
| Freeze (32°F) | Mar 15 | Feb 23 | Jan 29 |
| Hard (28°F) | Feb 28 | Feb 2 | Dec 31 |
| Severe (24°F) | Feb 8 | Jan 8 | Dec 16 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 10 | Mar 31 | Mar 23 | Mar 17 | Mar 12 | Mar 9 | Mar 5 | Mar 1 | Feb 24 |
| 32°F | Mar 15 | Mar 8 | Mar 3 | Feb 28 | Feb 23 | Feb 18 | Feb 12 | Feb 4 | Jan 29 |
| 28°F | Feb 28 | Feb 19 | Feb 12 | Feb 6 | Feb 2 | Jan 29 | Jan 22 | Jan 12 | Dec 31 |
| 24°F | Feb 8 | Jan 31 | Jan 24 | Jan 16 | Jan 8 | Jan 3 | Dec 30 | Dec 23 | Dec 16 |
| 20°F | Jan 28 | Jan 20 | Jan 11 | Jan 6 | Jan 3 | Dec 31 | Dec 25 | Dec 18 | Dec 11 |
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 27 | Nov 14 | Nov 28 |
| Freeze (32°F) | Nov 10 | Nov 24 | Dec 8 |
| Hard (28°F) | Nov 21 | Dec 6 | Dec 23 |
| Severe (24°F) | Dec 1 | Dec 18 | Jan 14 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 27 | Nov 3 | Nov 7 | Nov 11 | Nov 14 | Nov 16 | Nov 19 | Nov 22 | Nov 28 |
| 32°F | Nov 10 | Nov 15 | Nov 18 | Nov 21 | Nov 24 | Nov 27 | Dec 1 | Dec 4 | Dec 8 |
| 28°F | Nov 21 | Nov 26 | Nov 30 | Dec 2 | Dec 6 | Dec 9 | Dec 12 | Dec 17 | Dec 23 |
| 24°F | Dec 1 | Dec 5 | Dec 10 | Dec 14 | Dec 18 | Dec 23 | Dec 29 | Jan 3 | Jan 14 |
| 20°F | Dec 6 | Dec 12 | Dec 18 | Dec 24 | Dec 30 | Jan 2 | Jan 6 | Jan 12 | Jan 23 |
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: Maricopa 4 N, Az, about 7 miles away@if(!empty($station['elevation_ft'])), at 1,160 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 Maricopa, AZ?
On average, the last spring frost (32°F) around Maricopa, AZ is about Feb 23. In cooler years it can run later, so for a safer bet many gardeners wait until Jan 29.
When is the first frost in the fall?
The first fall frost around Maricopa, AZ typically arrives about Nov 24. 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 Feb 23 on average, or Jan 29 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 274 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 85138 Planting calendar → Arizona frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026