Cortaro, AZ frost dates
Last spring frostFeb 26median date
First fall frostDec 4median date
Growing season281 daysfrost-free
Hardiness zone9bZone 9b
How Cortaro compares
- In 8 years out of 10, the last spring frost in Cortaro falls between January 29 and March 18, a 48-day window. The first fall frost falls between November 17 and December 19.
- The median last frost is 49 days earlier than the Arizona median of Apr 16.
- Its 281-day growing season is longer than 95% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 6 days later than the zone 9b median of Feb 20. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9b chart.
- The weather station records an average of 20 nights a year at or below 32°F.
- Nearby Tucson, AZ, 27 km away, gets only light, occasional frost, a reminder of how much elevation and distance from the coast matter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | January 29 |
| 50% (median) | February 26 |
| 10% (safe for tender plants) | March 18 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 17 |
| 50% (median) | December 4 |
| 90% (late) | December 19 |
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 Cortaro, AZ
Cortaro, AZ frost dates — last frost Feb 26, first frost Dec 4, zone 9b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Dec 4 to Dec 18Transplant outside: Jan 29 to Feb 12
Start indoors: Dec 18 to Jan 1Start indoors: Dec 18 to Jan 1Transplant outside: Mar 12 to Mar 26
Start indoors: Dec 18 to Jan 1Start indoors: Dec 18 to Jan 1Transplant outside: Mar 12 to Mar 26
Start indoors: Jan 1 to Jan 15Transplant outside: Mar 5 to Mar 19
Start indoors: Jan 1 to Jan 15Transplant outside: Feb 5 to Feb 19Sow outdoors: Jan 29 to Mar 5Plant for fall: Oct 9 to Nov 6
Start indoors: Jan 1 to Jan 15Transplant outside: Jan 29 to Feb 12Sow outdoors: Jan 29 to Feb 12Plant for fall: Sep 25 to Oct 16
Start indoors: Jan 1 to Jan 15Transplant outside: Feb 12 to Feb 26Plant for fall: Aug 28 to Sep 18
Start indoors: Jan 1 to Jan 15Transplant outside: Feb 5 to Feb 19Plant for fall: Aug 28 to Sep 18
Start indoors: Jan 1 to Jan 15Transplant outside: Feb 12 to Feb 26Plant for fall: Aug 28 to Sep 18
Start indoors: Jan 15 to Jan 29Transplant outside: Mar 19 to Apr 2Sow outdoors: Mar 19 to Apr 2
Start indoors: Jan 15 to Jan 29Transplant outside: Mar 5 to Mar 19
Sow outdoors: Jan 15 to Feb 5Plant for fall: Sep 11 to Oct 2
Sow outdoors: Jan 15 to Feb 5Plant for fall: Oct 9 to Oct 30
Sow outdoors: Jan 22 to Mar 5Plant for fall: Oct 23 to Nov 13
Start indoors: Jan 29 to Feb 5Transplant outside: Mar 12 to Mar 19Sow outdoors: Mar 5 to Mar 19Plant for fall: Sep 18 to Oct 2
Start indoors: Jan 29 to Feb 5Sow outdoors: Mar 5 to Mar 19Plant for fall: Sep 25 to Oct 9
Start indoors: Jan 29 to Feb 5Sow outdoors: Mar 5 to Mar 19
Start indoors: Jan 29 to Feb 5Transplant outside: Mar 12 to Mar 26
Sow outdoors: Feb 5 to Mar 5Plant for fall: Sep 11 to Sep 25
Sow outdoors: Feb 5 to Mar 5Plant for fall: Sep 25 to Oct 9
Sow outdoors: Feb 5 to Feb 26
Sow outdoors: Feb 12 to Mar 12Plant for fall: Sep 25 to Oct 9
Sow outdoors: Feb 12 to Mar 5Plant for fall: Oct 9 to Oct 30
Sow outdoors: Mar 5 to Mar 26Plant for fall: Sep 18 to Oct 2
Sow outdoors: Mar 5 to Mar 19
Transplant outside: Mar 12 to Apr 2
Plant for fall: Nov 20 to Dec 25
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Cortaro, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Dec 4 – Dec 18 | Jan 29 – Feb 12 | — | — |
| Peppers | Dec 18 – Jan 1 | Mar 12 – Mar 26 | — | — |
| Eggplant | Dec 18 – Jan 1 | Mar 12 – Mar 26 | — | — |
| Tomatoes | Jan 1 – Jan 15 | Mar 5 – Mar 19 | — | — |
| Lettuce | Jan 1 – Jan 15 | Feb 5 – Feb 19 | Jan 29 – Mar 5 | Oct 9 – Nov 6 |
| Kale | Jan 1 – Jan 15 | Jan 29 – Feb 12 | Jan 29 – Feb 12 | Sep 25 – Oct 16 |
| Broccoli | Jan 1 – Jan 15 | Feb 12 – Feb 26 | — | Aug 28 – Sep 18 |
| Cabbage | Jan 1 – Jan 15 | Feb 5 – Feb 19 | — | Aug 28 – Sep 18 |
| Cauliflower | Jan 1 – Jan 15 | Feb 12 – Feb 26 | — | Aug 28 – Sep 18 |
| Okra | Jan 15 – Jan 29 | Mar 19 – Apr 2 | Mar 19 – Apr 2 | — |
| Basil | Jan 15 – Jan 29 | Mar 5 – Mar 19 | — | — |
| Peas | — | — | Jan 15 – Feb 5 | Sep 11 – Oct 2 |
| Spinach | — | — | Jan 15 – Feb 5 | Oct 9 – Oct 30 |
| Radishes | — | — | Jan 22 – Mar 5 | Oct 23 – Nov 13 |
| Cucumbers | Jan 29 – Feb 5 | Mar 12 – Mar 19 | Mar 5 – Mar 19 | Sep 18 – Oct 2 |
| Zucchini & Summer Squash | Jan 29 – Feb 5 | — | Mar 5 – Mar 19 | Sep 25 – Oct 9 |
| Winter Squash & Pumpkins | Jan 29 – Feb 5 | — | Mar 5 – Mar 19 | — |
| Melons & Watermelon | Jan 29 – Feb 5 | Mar 12 – Mar 26 | — | — |
| Carrots | — | — | Feb 5 – Mar 5 | Sep 11 – Sep 25 |
| Beets | — | — | Feb 5 – Mar 5 | Sep 25 – Oct 9 |
| Potatoes | — | — | Feb 5 – Feb 26 | — |
| Swiss Chard | — | — | Feb 12 – Mar 12 | Sep 25 – Oct 9 |
| Cilantro | — | — | Feb 12 – Mar 5 | Oct 9 – Oct 30 |
| Green Beans | — | — | Mar 5 – Mar 26 | Sep 18 – Oct 2 |
| Sweet Corn | — | — | Mar 5 – Mar 19 | — |
| Sweet Potatoes | — | Mar 12 – Apr 2 | — | — |
| Garlic | — | — | — | Nov 20 – Dec 25 |
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 Tohono Chul, AZ weather station, 15 km away (elevation 2,526 ft (770 m)).
Frost dates near Cortaro
- Rillito Feb 23 · Dec 6
- Marana Feb 23 · Dec 6
- Catalina Apr 2 · Nov 11
- Tucson Jan 20 · Dec 17
- Red Rock Feb 6 · Dec 9
- Mount Lemmon Apr 1 · Nov 19
- Oracle Mar 23 · Nov 22
- Picacho Feb 6 · Dec 9
- San Manuel Feb 4 · Dec 8
- Sahuarita Feb 25 · Nov 27
Frequently asked questions
When is the last frost in Cortaro, AZ?
The median last spring frost in Cortaro, AZ is February 26. There is still about a 10% chance of frost after March 18, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Cortaro, AZ?
The median first fall frost is December 4, with about a 10% chance of frost before November 17.
How long is the growing season in Cortaro, AZ?
About 281 days between the median last spring frost and first fall frost.
What planting zone is Cortaro, AZ?
Cortaro, AZ is in USDA hardiness zone 9b.