Saint Johns, AZ frost dates
Last spring frostMay 3median date
First fall frostOct 10median date
Growing season160 daysfrost-free
Hardiness zone6bZone 6b
How Saint Johns compares
- In 8 years out of 10, the last spring frost in Saint Johns falls between April 20 and May 19, a 29-day window. The first fall frost falls between September 30 and October 25.
- The median last frost is 17 days later than the Arizona median of Apr 16.
- Its 160-day growing season is longer than 28% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 11 days later than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 142 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 20 |
| 50% (median) | May 3 |
| 10% (safe for tender plants) | May 19 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 30 |
| 50% (median) | October 10 |
| 90% (late) | October 25 |
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 Saint Johns, AZ
Saint Johns, AZ frost dates — last frost May 3, first frost Oct 10, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Feb 8 to Feb 22Transplant outside: Apr 5 to Apr 19
Start indoors: Feb 22 to Mar 8Transplant outside: May 17 to May 31
Start indoors: Feb 22 to Mar 8Transplant outside: May 17 to May 31
Start indoors: Mar 8 to Mar 22Transplant outside: May 10 to May 24
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 12 to Apr 26Sow outdoors: Apr 5 to May 10Plant for fall: Aug 15 to Sep 12
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 5 to Apr 19Sow outdoors: Apr 5 to Apr 19Plant for fall: Aug 1 to Aug 22
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 19 to May 3Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 12 to Apr 26Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 19 to May 3Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 22 to Apr 5Transplant outside: May 24 to Jun 7Sow outdoors: May 24 to Jun 7
Start indoors: Mar 22 to Apr 5Transplant outside: May 10 to May 24
Sow outdoors: Mar 22 to Apr 12Plant for fall: Jul 18 to Aug 8
Sow outdoors: Mar 22 to Apr 12Plant for fall: Aug 15 to Sep 5
Sow outdoors: Mar 29 to May 10Plant for fall: Aug 29 to Sep 19
Start indoors: Apr 5 to Apr 12Transplant outside: May 17 to May 24Sow outdoors: May 10 to May 24Plant for fall: Jul 25 to Aug 8
Start indoors: Apr 5 to Apr 12Sow outdoors: May 10 to May 24Plant for fall: Aug 1 to Aug 15
Start indoors: Apr 5 to Apr 12Sow outdoors: May 10 to May 24
Start indoors: Apr 5 to Apr 12Transplant outside: May 17 to May 31
Sow outdoors: Apr 12 to May 10Plant for fall: Jul 18 to Aug 1
Sow outdoors: Apr 12 to May 10Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 12 to May 3
Sow outdoors: Apr 19 to May 17Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 19 to May 10Plant for fall: Aug 15 to Sep 5
Sow outdoors: May 10 to May 31Plant for fall: Jul 25 to Aug 8
Sow outdoors: May 10 to May 24
Transplant outside: May 17 to Jun 7
Plant for fall: Sep 26 to Oct 31
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Saint Johns, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 8 – Feb 22 | Apr 5 – Apr 19 | — | — |
| Peppers | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Eggplant | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Tomatoes | Mar 8 – Mar 22 | May 10 – May 24 | — | — |
| Lettuce | Mar 8 – Mar 22 | Apr 12 – Apr 26 | Apr 5 – May 10 | Aug 15 – Sep 12 |
| Kale | Mar 8 – Mar 22 | Apr 5 – Apr 19 | Apr 5 – Apr 19 | Aug 1 – Aug 22 |
| Broccoli | Mar 8 – Mar 22 | Apr 19 – May 3 | — | Jul 4 – Jul 25 |
| Cabbage | Mar 8 – Mar 22 | Apr 12 – Apr 26 | — | Jul 4 – Jul 25 |
| Cauliflower | Mar 8 – Mar 22 | Apr 19 – May 3 | — | Jul 4 – Jul 25 |
| Okra | Mar 22 – Apr 5 | May 24 – Jun 7 | May 24 – Jun 7 | — |
| Basil | Mar 22 – Apr 5 | May 10 – May 24 | — | — |
| Peas | — | — | Mar 22 – Apr 12 | Jul 18 – Aug 8 |
| Spinach | — | — | Mar 22 – Apr 12 | Aug 15 – Sep 5 |
| Radishes | — | — | Mar 29 – May 10 | Aug 29 – Sep 19 |
| Cucumbers | Apr 5 – Apr 12 | May 17 – May 24 | May 10 – May 24 | Jul 25 – Aug 8 |
| Zucchini & Summer Squash | Apr 5 – Apr 12 | — | May 10 – May 24 | Aug 1 – Aug 15 |
| Winter Squash & Pumpkins | Apr 5 – Apr 12 | — | May 10 – May 24 | — |
| Melons & Watermelon | Apr 5 – Apr 12 | May 17 – May 31 | — | — |
| Carrots | — | — | Apr 12 – May 10 | Jul 18 – Aug 1 |
| Beets | — | — | Apr 12 – May 10 | Aug 1 – Aug 15 |
| Potatoes | — | — | Apr 12 – May 3 | — |
| Swiss Chard | — | — | Apr 19 – May 17 | Aug 1 – Aug 15 |
| Cilantro | — | — | Apr 19 – May 10 | Aug 15 – Sep 5 |
| Green Beans | — | — | May 10 – May 31 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | May 10 – May 24 | — |
| Sweet Potatoes | — | May 17 – Jun 7 | — | — |
| Garlic | — | — | — | Sep 26 – Oct 31 |
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 St Johns Industrial Ap, AZ weather station, 2 km away (elevation 5,732 ft (1,747 m)).
Frost dates near Saint Johns
- Concho May 2 · Oct 14
- Springerville Jun 1 · Sep 26
- Vernon May 20 · Oct 11
- Eagar Jun 1 · Sep 26
- Greer Jun 5 · Sep 29
- Show Low May 5 · Oct 15
- Nutrioso Jun 15 · Sep 21
- Snowflake May 11 · Oct 10
- Mcnary May 20 · Oct 11
- Taylor May 11 · Oct 10
Frequently asked questions
When is the last frost in Saint Johns, AZ?
The median last spring frost in Saint Johns, AZ is May 3. There is still about a 10% chance of frost after May 19, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Saint Johns, AZ?
The median first fall frost is October 10, with about a 10% chance of frost before September 30.
How long is the growing season in Saint Johns, AZ?
About 160 days between the median last spring frost and first fall frost.
What planting zone is Saint Johns, AZ?
Saint Johns, AZ is in USDA hardiness zone 6b.