Window Rock, AZ frost dates
Last spring frostMay 29median date
First fall frostSep 28median date
Growing season122 daysfrost-free
Hardiness zone6bZone 6b
How Window Rock compares
- In 8 years out of 10, the last spring frost in Window Rock falls between May 12 and June 10, a 29-day window. The first fall frost falls between September 16 and October 8.
- The median last frost is 43 days later than the Arizona median of Apr 16.
- Its 122-day growing season is longer than 7% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 37 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 196 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 12 |
| 50% (median) | May 29 |
| 10% (safe for tender plants) | June 10 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 16 |
| 50% (median) | September 28 |
| 90% (late) | October 8 |
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 Window Rock, AZ
Window Rock, AZ frost dates — last frost May 29, first frost Sep 28, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Mar 6 to Mar 20Transplant outside: May 1 to May 15
Start indoors: Mar 20 to Apr 3Transplant outside: Jun 12 to Jun 26
Start indoors: Mar 20 to Apr 3Transplant outside: Jun 12 to Jun 26
Start indoors: Apr 3 to Apr 17Transplant outside: Jun 5 to Jun 19
Start indoors: Apr 3 to Apr 17Transplant outside: May 8 to May 22Sow outdoors: May 1 to Jun 5Plant for fall: Aug 3 to Aug 31
Start indoors: Apr 3 to Apr 17Transplant outside: May 1 to May 15Sow outdoors: May 1 to May 15Plant for fall: Jul 20 to Aug 10
Start indoors: Apr 3 to Apr 17Transplant outside: May 15 to May 29Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 3 to Apr 17Transplant outside: May 8 to May 22Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 3 to Apr 17Transplant outside: May 15 to May 29Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 17 to May 1Transplant outside: Jun 19 to Jul 3Sow outdoors: Jun 19 to Jul 3
Start indoors: Apr 17 to May 1Transplant outside: Jun 5 to Jun 19
Sow outdoors: Apr 17 to May 8Plant for fall: Jul 6 to Jul 27
Sow outdoors: Apr 17 to May 8Plant for fall: Aug 3 to Aug 24
Sow outdoors: Apr 24 to Jun 5Plant for fall: Aug 17 to Sep 7
Start indoors: May 1 to May 8Transplant outside: Jun 12 to Jun 19Sow outdoors: Jun 5 to Jun 19Plant for fall: Jul 13 to Jul 27
Start indoors: May 1 to May 8Sow outdoors: Jun 5 to Jun 19Plant for fall: Jul 20 to Aug 3
Start indoors: May 1 to May 8Sow outdoors: Jun 5 to Jun 19
Start indoors: May 1 to May 8Transplant outside: Jun 12 to Jun 26
Sow outdoors: May 8 to Jun 5Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 8 to Jun 5Plant for fall: Jul 20 to Aug 3
Sow outdoors: May 8 to May 29
Sow outdoors: May 15 to Jun 12Plant for fall: Jul 20 to Aug 3
Sow outdoors: May 15 to Jun 5Plant for fall: Aug 3 to Aug 24
Sow outdoors: Jun 5 to Jun 26Plant for fall: Jul 13 to Jul 27
Sow outdoors: Jun 5 to Jun 19
Transplant outside: Jun 12 to Jul 3
Plant for fall: Sep 14 to Oct 19
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Window Rock, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 6 – Mar 20 | May 1 – May 15 | — | — |
| Peppers | Mar 20 – Apr 3 | Jun 12 – Jun 26 | — | — |
| Eggplant | Mar 20 – Apr 3 | Jun 12 – Jun 26 | — | — |
| Tomatoes | Apr 3 – Apr 17 | Jun 5 – Jun 19 | — | — |
| Lettuce | Apr 3 – Apr 17 | May 8 – May 22 | May 1 – Jun 5 | Aug 3 – Aug 31 |
| Kale | Apr 3 – Apr 17 | May 1 – May 15 | May 1 – May 15 | Jul 20 – Aug 10 |
| Broccoli | Apr 3 – Apr 17 | May 15 – May 29 | — | Jun 22 – Jul 13 |
| Cabbage | Apr 3 – Apr 17 | May 8 – May 22 | — | Jun 22 – Jul 13 |
| Cauliflower | Apr 3 – Apr 17 | May 15 – May 29 | — | Jun 22 – Jul 13 |
| Okra | Apr 17 – May 1 | Jun 19 – Jul 3 | Jun 19 – Jul 3 | — |
| Basil | Apr 17 – May 1 | Jun 5 – Jun 19 | — | — |
| Peas | — | — | Apr 17 – May 8 | Jul 6 – Jul 27 |
| Spinach | — | — | Apr 17 – May 8 | Aug 3 – Aug 24 |
| Radishes | — | — | Apr 24 – Jun 5 | Aug 17 – Sep 7 |
| Cucumbers | May 1 – May 8 | Jun 12 – Jun 19 | Jun 5 – Jun 19 | Jul 13 – Jul 27 |
| Zucchini & Summer Squash | May 1 – May 8 | — | Jun 5 – Jun 19 | Jul 20 – Aug 3 |
| Winter Squash & Pumpkins | May 1 – May 8 | — | Jun 5 – Jun 19 | — |
| Melons & Watermelon | May 1 – May 8 | Jun 12 – Jun 26 | — | — |
| Carrots | — | — | May 8 – Jun 5 | Jul 6 – Jul 20 |
| Beets | — | — | May 8 – Jun 5 | Jul 20 – Aug 3 |
| Potatoes | — | — | May 8 – May 29 | — |
| Swiss Chard | — | — | May 15 – Jun 12 | Jul 20 – Aug 3 |
| Cilantro | — | — | May 15 – Jun 5 | Aug 3 – Aug 24 |
| Green Beans | — | — | Jun 5 – Jun 26 | Jul 13 – Jul 27 |
| Sweet Corn | — | — | Jun 5 – Jun 19 | — |
| Sweet Potatoes | — | Jun 12 – Jul 3 | — | — |
| Garlic | — | — | — | Sep 14 – Oct 19 |
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 Window Rock Ap, AZ weather station, 2 km away (elevation 6,739 ft (2,054 m)).
Frost dates near Window Rock
- Saint Michaels May 29 · Sep 28
- Fort Defiance May 29 · Sep 28
- Lupton May 22 · Oct 8
- Nazlini May 15 · Oct 10
- Ganado May 15 · Oct 10
- Houck May 22 · Oct 8
- Sanders May 22 · Oct 8
- Chambers May 22 · Oct 8
- Petrified Forest Natl Pk May 22 · Oct 8
- Red Valley May 22 · Oct 8
Frequently asked questions
When is the last frost in Window Rock, AZ?
The median last spring frost in Window Rock, AZ is May 29. There is still about a 10% chance of frost after June 10, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Window Rock, AZ?
The median first fall frost is September 28, with about a 10% chance of frost before September 16.
How long is the growing season in Window Rock, AZ?
About 122 days between the median last spring frost and first fall frost.
What planting zone is Window Rock, AZ?
Window Rock, AZ is in USDA hardiness zone 6b.