Rio Rico, AZ frost dates
Last spring frostApr 5median date
First fall frostNov 10median date
Growing season219 daysfrost-free
Hardiness zone8bZone 8b
How Rio Rico compares
- In 8 years out of 10, the last spring frost in Rio Rico falls between March 13 and April 25, a 43-day window. The first fall frost falls between October 21 and November 27.
- The median last frost is 11 days earlier than the Arizona median of Apr 16.
- Its 219-day growing season is longer than 59% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 20 days later than the zone 8b median of Mar 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 8b chart.
- The weather station records an average of 60 nights a year at or below 32°F.
- Nearby Tucson, AZ, 81 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) | March 13 |
| 50% (median) | April 5 |
| 10% (safe for tender plants) | April 25 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 21 |
| 50% (median) | November 10 |
| 90% (late) | November 27 |
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 Rio Rico, AZ
Rio Rico, AZ frost dates — last frost Apr 5, first frost Nov 10, zone 8b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Jan 11 to Jan 25Transplant outside: Mar 8 to Mar 22
Start indoors: Jan 25 to Feb 8Transplant outside: Apr 19 to May 3
Start indoors: Jan 25 to Feb 8Transplant outside: Apr 19 to May 3
Start indoors: Feb 8 to Feb 22Transplant outside: Apr 12 to Apr 26
Start indoors: Feb 8 to Feb 22Transplant outside: Mar 15 to Mar 29Sow outdoors: Mar 8 to Apr 12Plant for fall: Sep 15 to Oct 13
Start indoors: Feb 8 to Feb 22Transplant outside: Mar 8 to Mar 22Sow outdoors: Mar 8 to Mar 22Plant for fall: Sep 1 to Sep 22
Start indoors: Feb 8 to Feb 22Transplant outside: Mar 22 to Apr 5Plant for fall: Aug 4 to Aug 25
Start indoors: Feb 8 to Feb 22Transplant outside: Mar 15 to Mar 29Plant for fall: Aug 4 to Aug 25
Start indoors: Feb 8 to Feb 22Transplant outside: Mar 22 to Apr 5Plant for fall: Aug 4 to Aug 25
Start indoors: Feb 22 to Mar 8Transplant outside: Apr 26 to May 10Sow outdoors: Apr 26 to May 10
Start indoors: Feb 22 to Mar 8Transplant outside: Apr 12 to Apr 26
Sow outdoors: Feb 22 to Mar 15Plant for fall: Aug 18 to Sep 8
Sow outdoors: Feb 22 to Mar 15Plant for fall: Sep 15 to Oct 6
Sow outdoors: Mar 1 to Apr 12Plant for fall: Sep 29 to Oct 20
Start indoors: Mar 8 to Mar 15Transplant outside: Apr 19 to Apr 26Sow outdoors: Apr 12 to Apr 26Plant for fall: Aug 25 to Sep 8
Start indoors: Mar 8 to Mar 15Sow outdoors: Apr 12 to Apr 26Plant for fall: Sep 1 to Sep 15
Start indoors: Mar 8 to Mar 15Sow outdoors: Apr 12 to Apr 26
Start indoors: Mar 8 to Mar 15Transplant outside: Apr 19 to May 3
Sow outdoors: Mar 15 to Apr 12Plant for fall: Aug 18 to Sep 1
Sow outdoors: Mar 15 to Apr 12Plant for fall: Sep 1 to Sep 15
Sow outdoors: Mar 15 to Apr 5
Sow outdoors: Mar 22 to Apr 19Plant for fall: Sep 1 to Sep 15
Sow outdoors: Mar 22 to Apr 12Plant for fall: Sep 15 to Oct 6
Sow outdoors: Apr 12 to May 3Plant for fall: Aug 25 to Sep 8
Sow outdoors: Apr 12 to Apr 26
Transplant outside: Apr 19 to May 10
Plant for fall: Oct 27 to Dec 1
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Rio Rico, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 11 – Jan 25 | Mar 8 – Mar 22 | — | — |
| Peppers | Jan 25 – Feb 8 | Apr 19 – May 3 | — | — |
| Eggplant | Jan 25 – Feb 8 | Apr 19 – May 3 | — | — |
| Tomatoes | Feb 8 – Feb 22 | Apr 12 – Apr 26 | — | — |
| Lettuce | Feb 8 – Feb 22 | Mar 15 – Mar 29 | Mar 8 – Apr 12 | Sep 15 – Oct 13 |
| Kale | Feb 8 – Feb 22 | Mar 8 – Mar 22 | Mar 8 – Mar 22 | Sep 1 – Sep 22 |
| Broccoli | Feb 8 – Feb 22 | Mar 22 – Apr 5 | — | Aug 4 – Aug 25 |
| Cabbage | Feb 8 – Feb 22 | Mar 15 – Mar 29 | — | Aug 4 – Aug 25 |
| Cauliflower | Feb 8 – Feb 22 | Mar 22 – Apr 5 | — | Aug 4 – Aug 25 |
| Okra | Feb 22 – Mar 8 | Apr 26 – May 10 | Apr 26 – May 10 | — |
| Basil | Feb 22 – Mar 8 | Apr 12 – Apr 26 | — | — |
| Peas | — | — | Feb 22 – Mar 15 | Aug 18 – Sep 8 |
| Spinach | — | — | Feb 22 – Mar 15 | Sep 15 – Oct 6 |
| Radishes | — | — | Mar 1 – Apr 12 | Sep 29 – Oct 20 |
| Cucumbers | Mar 8 – Mar 15 | Apr 19 – Apr 26 | Apr 12 – Apr 26 | Aug 25 – Sep 8 |
| Zucchini & Summer Squash | Mar 8 – Mar 15 | — | Apr 12 – Apr 26 | Sep 1 – Sep 15 |
| Winter Squash & Pumpkins | Mar 8 – Mar 15 | — | Apr 12 – Apr 26 | — |
| Melons & Watermelon | Mar 8 – Mar 15 | Apr 19 – May 3 | — | — |
| Carrots | — | — | Mar 15 – Apr 12 | Aug 18 – Sep 1 |
| Beets | — | — | Mar 15 – Apr 12 | Sep 1 – Sep 15 |
| Potatoes | — | — | Mar 15 – Apr 5 | — |
| Swiss Chard | — | — | Mar 22 – Apr 19 | Sep 1 – Sep 15 |
| Cilantro | — | — | Mar 22 – Apr 12 | Sep 15 – Oct 6 |
| Green Beans | — | — | Apr 12 – May 3 | Aug 25 – Sep 8 |
| Sweet Corn | — | — | Apr 12 – Apr 26 | — |
| Sweet Potatoes | — | Apr 19 – May 10 | — | — |
| Garlic | — | — | — | Oct 27 – Dec 1 |
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 Tumacacori Nm, AZ weather station, 7 km away (elevation 3,268 ft (996 m)).
Frost dates near Rio Rico
- Tumacacori Apr 5 · Nov 10
- Tubac Apr 5 · Nov 10
- Nogales Apr 16 · Nov 2
- Amado Apr 5 · Nov 10
- Arivaca Mar 21 · Nov 20
- Patagonia Apr 23 · Oct 30
- Green Valley Feb 25 · Nov 27
- Sasabe Mar 21 · Nov 20
- Sonoita Mar 28 · Nov 21
- Sahuarita Feb 25 · Nov 27
Frequently asked questions
When is the last frost in Rio Rico, AZ?
The median last spring frost in Rio Rico, AZ is April 5. There is still about a 10% chance of frost after April 25, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Rio Rico, AZ?
The median first fall frost is November 10, with about a 10% chance of frost before October 21.
How long is the growing season in Rio Rico, AZ?
About 219 days between the median last spring frost and first fall frost.
What planting zone is Rio Rico, AZ?
Rio Rico, AZ is in USDA hardiness zone 8b.