Congress, AZ frost dates
Last spring frostMar 7median date
First fall frostNov 20median date
Growing season258 daysfrost-free
Hardiness zone9aZone 9a
How Congress compares
- In 8 years out of 10, the last spring frost in Congress falls between February 14 and April 8, a 53-day window. The first fall frost falls between November 4 and December 5.
- The median last frost is 40 days earlier than the Arizona median of Apr 16.
- Its 258-day growing season is longer than 86% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 4 days later than the zone 9a median of Mar 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9a chart.
- The weather station records an average of 47 nights a year at or below 32°F.
- Nearby Surprise, AZ, 69 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) | February 14 |
| 50% (median) | March 7 |
| 10% (safe for tender plants) | April 8 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 4 |
| 50% (median) | November 20 |
| 90% (late) | December 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 Congress, AZ
Congress, AZ frost dates — last frost Mar 7, first frost Nov 20, zone 9a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Dec 13 to Dec 27Transplant outside: Feb 7 to Feb 21
Start indoors: Dec 27 to Jan 10Start indoors: Dec 27 to Jan 10Transplant outside: Mar 21 to Apr 4
Start indoors: Dec 27 to Jan 10Start indoors: Dec 27 to Jan 10Transplant outside: Mar 21 to Apr 4
Start indoors: Jan 10 to Jan 24Transplant outside: Mar 14 to Mar 28
Start indoors: Jan 10 to Jan 24Transplant outside: Feb 14 to Feb 28Sow outdoors: Feb 7 to Mar 14Plant for fall: Sep 25 to Oct 23
Start indoors: Jan 10 to Jan 24Transplant outside: Feb 7 to Feb 21Sow outdoors: Feb 7 to Feb 21Plant for fall: Sep 11 to Oct 2
Start indoors: Jan 10 to Jan 24Transplant outside: Feb 21 to Mar 7Plant for fall: Aug 14 to Sep 4
Start indoors: Jan 10 to Jan 24Transplant outside: Feb 14 to Feb 28Plant for fall: Aug 14 to Sep 4
Start indoors: Jan 10 to Jan 24Transplant outside: Feb 21 to Mar 7Plant for fall: Aug 14 to Sep 4
Start indoors: Jan 24 to Feb 7Transplant outside: Mar 28 to Apr 11Sow outdoors: Mar 28 to Apr 11
Start indoors: Jan 24 to Feb 7Transplant outside: Mar 14 to Mar 28
Sow outdoors: Jan 24 to Feb 14Plant for fall: Aug 28 to Sep 18
Sow outdoors: Jan 24 to Feb 14Plant for fall: Sep 25 to Oct 16
Sow outdoors: Jan 31 to Mar 14Plant for fall: Oct 9 to Oct 30
Start indoors: Feb 7 to Feb 14Transplant outside: Mar 21 to Mar 28Sow outdoors: Mar 14 to Mar 28Plant for fall: Sep 4 to Sep 18
Start indoors: Feb 7 to Feb 14Sow outdoors: Mar 14 to Mar 28Plant for fall: Sep 11 to Sep 25
Start indoors: Feb 7 to Feb 14Sow outdoors: Mar 14 to Mar 28
Start indoors: Feb 7 to Feb 14Transplant outside: Mar 21 to Apr 4
Sow outdoors: Feb 14 to Mar 14Plant for fall: Aug 28 to Sep 11
Sow outdoors: Feb 14 to Mar 14Plant for fall: Sep 11 to Sep 25
Sow outdoors: Feb 14 to Mar 7
Sow outdoors: Feb 21 to Mar 21Plant for fall: Sep 11 to Sep 25
Sow outdoors: Feb 21 to Mar 14Plant for fall: Sep 25 to Oct 16
Sow outdoors: Mar 14 to Apr 4Plant for fall: Sep 4 to Sep 18
Sow outdoors: Mar 14 to Mar 28
Transplant outside: Mar 21 to Apr 11
Plant for fall: Nov 6 to Dec 11
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Congress, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Dec 13 – Dec 27 | Feb 7 – Feb 21 | — | — |
| Peppers | Dec 27 – Jan 10 | Mar 21 – Apr 4 | — | — |
| Eggplant | Dec 27 – Jan 10 | Mar 21 – Apr 4 | — | — |
| Tomatoes | Jan 10 – Jan 24 | Mar 14 – Mar 28 | — | — |
| Lettuce | Jan 10 – Jan 24 | Feb 14 – Feb 28 | Feb 7 – Mar 14 | Sep 25 – Oct 23 |
| Kale | Jan 10 – Jan 24 | Feb 7 – Feb 21 | Feb 7 – Feb 21 | Sep 11 – Oct 2 |
| Broccoli | Jan 10 – Jan 24 | Feb 21 – Mar 7 | — | Aug 14 – Sep 4 |
| Cabbage | Jan 10 – Jan 24 | Feb 14 – Feb 28 | — | Aug 14 – Sep 4 |
| Cauliflower | Jan 10 – Jan 24 | Feb 21 – Mar 7 | — | Aug 14 – Sep 4 |
| Okra | Jan 24 – Feb 7 | Mar 28 – Apr 11 | Mar 28 – Apr 11 | — |
| Basil | Jan 24 – Feb 7 | Mar 14 – Mar 28 | — | — |
| Peas | — | — | Jan 24 – Feb 14 | Aug 28 – Sep 18 |
| Spinach | — | — | Jan 24 – Feb 14 | Sep 25 – Oct 16 |
| Radishes | — | — | Jan 31 – Mar 14 | Oct 9 – Oct 30 |
| Cucumbers | Feb 7 – Feb 14 | Mar 21 – Mar 28 | Mar 14 – Mar 28 | Sep 4 – Sep 18 |
| Zucchini & Summer Squash | Feb 7 – Feb 14 | — | Mar 14 – Mar 28 | Sep 11 – Sep 25 |
| Winter Squash & Pumpkins | Feb 7 – Feb 14 | — | Mar 14 – Mar 28 | — |
| Melons & Watermelon | Feb 7 – Feb 14 | Mar 21 – Apr 4 | — | — |
| Carrots | — | — | Feb 14 – Mar 14 | Aug 28 – Sep 11 |
| Beets | — | — | Feb 14 – Mar 14 | Sep 11 – Sep 25 |
| Potatoes | — | — | Feb 14 – Mar 7 | — |
| Swiss Chard | — | — | Feb 21 – Mar 21 | Sep 11 – Sep 25 |
| Cilantro | — | — | Feb 21 – Mar 14 | Sep 25 – Oct 16 |
| Green Beans | — | — | Mar 14 – Apr 4 | Sep 4 – Sep 18 |
| Sweet Corn | — | — | Mar 14 – Mar 28 | — |
| Sweet Potatoes | — | Mar 21 – Apr 11 | — | — |
| Garlic | — | — | — | Nov 6 – Dec 11 |
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 Wickenburg, AZ weather station, 22 km away (elevation 2,096 ft (639 m)).
Frost dates near Congress
- Yarnell Mar 7 · Nov 20
- Wickenburg Mar 7 · Nov 20
- Kirkland Apr 7 · Nov 12
- Skull Valley Apr 30 · Oct 20
- Morristown Feb 5 · Dec 11
- Crown King Apr 5 · Nov 17
- Wittmann Feb 5 · Dec 11
- Aguila Mar 17 · Nov 19
- Prescott Apr 30 · Oct 20
- Bagdad Apr 7 · Nov 12
Frequently asked questions
When is the last frost in Congress, AZ?
The median last spring frost in Congress, AZ is March 7. There is still about a 10% chance of frost after April 8, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Congress, AZ?
The median first fall frost is November 20, with about a 10% chance of frost before November 4.
How long is the growing season in Congress, AZ?
About 258 days between the median last spring frost and first fall frost.
What planting zone is Congress, AZ?
Congress, AZ is in USDA hardiness zone 9a.