Last spring frost
Apr 2
Frost Dates for Oro Valley, AZ
First fall frost
Nov 11
Growing season
222 days
Hardiness zone
9a
In an average year around Oro Valley, AZ, the last spring frost (32°F) is about Apr 2 and the first fall frost is about Nov 11, giving roughly a 222-day growing season. To be safe most years, wait until Mar 16 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 5 | Apr 18 | Apr 4 |
| Freeze (32°F) | Apr 18 | Apr 2 | Mar 16 |
| Hard (28°F) | Apr 1 | Mar 12 | Feb 22 |
| Severe (24°F) | Mar 12 | Feb 21 | Jan 24 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 5 | Apr 30 | Apr 25 | Apr 21 | Apr 18 | Apr 15 | Apr 11 | Apr 8 | Apr 4 |
| 32°F | Apr 18 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 26 | Mar 21 | Mar 16 |
| 28°F | Apr 1 | Mar 27 | Mar 21 | Mar 16 | Mar 12 | Mar 9 | Mar 5 | Mar 2 | Feb 22 |
| 24°F | Mar 12 | Mar 7 | Mar 3 | Feb 27 | Feb 21 | Feb 15 | Feb 10 | Feb 4 | Jan 24 |
| 20°F | Feb 26 | Feb 16 | Feb 8 | Feb 2 | Jan 27 | Jan 19 | Jan 10 | Jan 2 | Dec 21 |
| 16°F | Feb 14 | Feb 3 | Jan 26 | Jan 17 | Jan 10 | Jan 2 | Dec 29 | Dec 19 | Dec 4 |
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 18 | Nov 1 | Nov 17 |
| Freeze (32°F) | Oct 26 | Nov 11 | Nov 29 |
| Hard (28°F) | Nov 3 | Nov 21 | Dec 10 |
| Severe (24°F) | Nov 13 | Dec 4 | Dec 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 18 | Oct 23 | Oct 27 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 17 |
| 32°F | Oct 26 | Oct 31 | Nov 4 | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 23 | Nov 29 |
| 28°F | Nov 3 | Nov 9 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 30 | Dec 4 | Dec 10 |
| 24°F | Nov 13 | Nov 20 | Nov 25 | Nov 29 | Dec 4 | Dec 9 | Dec 12 | Dec 17 | Dec 25 |
| 20°F | Nov 24 | Dec 1 | Dec 8 | Dec 14 | Dec 19 | Dec 26 | Jan 2 | Jan 16 | Jan 29 |
| 16°F | Nov 28 | Dec 11 | Dec 22 | Dec 29 | Jan 2 | Jan 9 | Jan 18 | Jan 31 | Feb 10 |
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: Catalina Sp, Az, about 1 miles away@if(!empty($station['elevation_ft'])), at 2,707 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 Oro Valley, AZ?
On average, the last spring frost (32°F) around Oro Valley, AZ is about Apr 2. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 16.
When is the first frost in the fall?
The first fall frost around Oro Valley, AZ typically arrives about Nov 11. 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 2 on average, or Mar 16 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 222 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 85737 Planting calendar → Arizona frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026