Duncan, AZ frost dates
Last spring frostApr 24median date
First fall frostOct 25median date
Growing season184 daysfrost-free
Hardiness zone8aZone 8a
How Duncan compares
- In 8 years out of 10, the last spring frost in Duncan falls between April 8 and May 8, a 30-day window. The first fall frost falls between October 11 and November 5.
- The median last frost is 8 days later than the Arizona median of Apr 16.
- Its 184-day growing season is longer than 41% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 26 days later than the zone 8a median of Mar 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 8a chart.
- The weather station records an average of 113 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 8 |
| 50% (median) | April 24 |
| 10% (safe for tender plants) | May 8 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 11 |
| 50% (median) | October 25 |
| 90% (late) | November 5 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Duncan, AZ
Duncan, AZ frost dates — last frost Apr 24, first frost Oct 25, zone 8a. whenisthelastfrost.com
Crop
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Start indoors: Jan 30 to Feb 13Transplant outside: Mar 27 to Apr 10
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 27 to Mar 13Transplant outside: May 1 to May 15
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Sow outdoors: Mar 27 to May 1Plant for fall: Aug 30 to Sep 27
Start indoors: Feb 27 to Mar 13Transplant outside: Mar 27 to Apr 10Sow outdoors: Mar 27 to Apr 10Plant for fall: Aug 16 to Sep 6
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 19 to Aug 9
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Plant for fall: Jul 19 to Aug 9
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 19 to Aug 9
Start indoors: Mar 13 to Mar 27Transplant outside: May 15 to May 29Sow outdoors: May 15 to May 29
Start indoors: Mar 13 to Mar 27Transplant outside: May 1 to May 15
Sow outdoors: Mar 13 to Apr 3Plant for fall: Aug 2 to Aug 23
Sow outdoors: Mar 13 to Apr 3Plant for fall: Aug 30 to Sep 20
Sow outdoors: Mar 20 to May 1Plant for fall: Sep 13 to Oct 4
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 15Sow outdoors: May 1 to May 15Plant for fall: Aug 9 to Aug 23
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15Plant for fall: Aug 16 to Aug 30
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 22
Sow outdoors: Apr 3 to May 1Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 3 to May 1Plant for fall: Aug 16 to Aug 30
Sow outdoors: Apr 3 to Apr 24
Sow outdoors: Apr 10 to May 8Plant for fall: Aug 16 to Aug 30
Sow outdoors: Apr 10 to May 1Plant for fall: Aug 30 to Sep 20
Sow outdoors: May 1 to May 22Plant for fall: Aug 9 to Aug 23
Sow outdoors: May 1 to May 15
Transplant outside: May 8 to May 29
Plant for fall: Oct 11 to Nov 15
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Duncan, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 30 – Feb 13 | Mar 27 – Apr 10 | — | — |
| Peppers | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Eggplant | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Tomatoes | Feb 27 – Mar 13 | May 1 – May 15 | — | — |
| Lettuce | Feb 27 – Mar 13 | Apr 3 – Apr 17 | Mar 27 – May 1 | Aug 30 – Sep 27 |
| Kale | Feb 27 – Mar 13 | Mar 27 – Apr 10 | Mar 27 – Apr 10 | Aug 16 – Sep 6 |
| Broccoli | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 19 – Aug 9 |
| Cabbage | Feb 27 – Mar 13 | Apr 3 – Apr 17 | — | Jul 19 – Aug 9 |
| Cauliflower | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 19 – Aug 9 |
| Okra | Mar 13 – Mar 27 | May 15 – May 29 | May 15 – May 29 | — |
| Basil | Mar 13 – Mar 27 | May 1 – May 15 | — | — |
| Peas | — | — | Mar 13 – Apr 3 | Aug 2 – Aug 23 |
| Spinach | — | — | Mar 13 – Apr 3 | Aug 30 – Sep 20 |
| Radishes | — | — | Mar 20 – May 1 | Sep 13 – Oct 4 |
| Cucumbers | Mar 27 – Apr 3 | May 8 – May 15 | May 1 – May 15 | Aug 9 – Aug 23 |
| Zucchini & Summer Squash | Mar 27 – Apr 3 | — | May 1 – May 15 | Aug 16 – Aug 30 |
| Winter Squash & Pumpkins | Mar 27 – Apr 3 | — | May 1 – May 15 | — |
| Melons & Watermelon | Mar 27 – Apr 3 | May 8 – May 22 | — | — |
| Carrots | — | — | Apr 3 – May 1 | Aug 2 – Aug 16 |
| Beets | — | — | Apr 3 – May 1 | Aug 16 – Aug 30 |
| Potatoes | — | — | Apr 3 – Apr 24 | — |
| Swiss Chard | — | — | Apr 10 – May 8 | Aug 16 – Aug 30 |
| Cilantro | — | — | Apr 10 – May 1 | Aug 30 – Sep 20 |
| Green Beans | — | — | May 1 – May 22 | Aug 9 – Aug 23 |
| Sweet Corn | — | — | May 1 – May 15 | — |
| Sweet Potatoes | — | May 8 – May 29 | — | — |
| Garlic | — | — | — | Oct 11 – Nov 15 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Duncan, AZ weather station, 17 km away (elevation 3,661 ft (1,116 m)).
Frost dates near Duncan
- Morenci Feb 26 · Nov 23
- Clifton Feb 26 · Nov 23
- Solomon Mar 25 · Nov 9
- Safford Mar 25 · Nov 9
- Thatcher Mar 25 · Nov 9
- Central Mar 25 · Nov 9
- Pima Apr 1 · Nov 6
- Eden Apr 1 · Nov 6
- Bowie Apr 1 · Nov 6
- Fort Thomas Apr 1 · Nov 6
Frequently asked questions
When is the last frost in Duncan, AZ?
The median last spring frost in Duncan, AZ is April 24. There is still about a 10% chance of frost after May 8, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Duncan, AZ?
The median first fall frost is October 25, with about a 10% chance of frost before October 11.
How long is the growing season in Duncan, AZ?
About 184 days between the median last spring frost and first fall frost.
What planting zone is Duncan, AZ?
Duncan, AZ is in USDA hardiness zone 8a.