Williams, AZ frost dates
Last spring frostMay 9median date
First fall frostOct 19median date
Growing season163 daysfrost-free
Hardiness zone7aZone 7a
How Williams compares
- In 8 years out of 10, the last spring frost in Williams falls between April 24 and May 27, a 33-day window. The first fall frost falls between October 3 and November 3.
- The median last frost is 23 days later than the Arizona median of Apr 16.
- Its 163-day growing season is longer than 31% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 23 days later than the zone 7a median of Apr 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 7a chart.
- The weather station records an average of 144 nights a year at or below 32°F.
- Compared with Flagstaff, AZ, 62 km away, the last frost here is 26 days earlier than there and the growing season is 47 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 24 |
| 50% (median) | May 9 |
| 10% (safe for tender plants) | May 27 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 3 |
| 50% (median) | October 19 |
| 90% (late) | November 3 |
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 Williams, AZ
Williams, AZ frost dates — last frost May 9, first frost Oct 19, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Feb 14 to Feb 28Transplant outside: Apr 11 to Apr 25
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Mar 14 to Mar 28Transplant outside: May 16 to May 30
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Sow outdoors: Apr 11 to May 16Plant for fall: Aug 24 to Sep 21
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 11 to Apr 25Sow outdoors: Apr 11 to Apr 25Plant for fall: Aug 10 to Aug 31
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jul 13 to Aug 3
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Plant for fall: Jul 13 to Aug 3
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jul 13 to Aug 3
Start indoors: Mar 28 to Apr 11Transplant outside: May 30 to Jun 13Sow outdoors: May 30 to Jun 13
Start indoors: Mar 28 to Apr 11Transplant outside: May 16 to May 30
Sow outdoors: Mar 28 to Apr 18Plant for fall: Jul 27 to Aug 17
Sow outdoors: Mar 28 to Apr 18Plant for fall: Aug 24 to Sep 14
Sow outdoors: Apr 4 to May 16Plant for fall: Sep 7 to Sep 28
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to May 30Sow outdoors: May 16 to May 30Plant for fall: Aug 3 to Aug 17
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30Plant for fall: Aug 10 to Aug 24
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to Jun 6
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 27 to Aug 10
Sow outdoors: Apr 18 to May 16Plant for fall: Aug 10 to Aug 24
Sow outdoors: Apr 18 to May 9
Sow outdoors: Apr 25 to May 23Plant for fall: Aug 10 to Aug 24
Sow outdoors: Apr 25 to May 16Plant for fall: Aug 24 to Sep 14
Sow outdoors: May 16 to Jun 6Plant for fall: Aug 3 to Aug 17
Sow outdoors: May 16 to May 30
Transplant outside: May 23 to Jun 13
Plant for fall: Oct 5 to Nov 9
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Williams, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 14 – Feb 28 | Apr 11 – Apr 25 | — | — |
| Peppers | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Eggplant | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Tomatoes | Mar 14 – Mar 28 | May 16 – May 30 | — | — |
| Lettuce | Mar 14 – Mar 28 | Apr 18 – May 2 | Apr 11 – May 16 | Aug 24 – Sep 21 |
| Kale | Mar 14 – Mar 28 | Apr 11 – Apr 25 | Apr 11 – Apr 25 | Aug 10 – Aug 31 |
| Broccoli | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jul 13 – Aug 3 |
| Cabbage | Mar 14 – Mar 28 | Apr 18 – May 2 | — | Jul 13 – Aug 3 |
| Cauliflower | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jul 13 – Aug 3 |
| Okra | Mar 28 – Apr 11 | May 30 – Jun 13 | May 30 – Jun 13 | — |
| Basil | Mar 28 – Apr 11 | May 16 – May 30 | — | — |
| Peas | — | — | Mar 28 – Apr 18 | Jul 27 – Aug 17 |
| Spinach | — | — | Mar 28 – Apr 18 | Aug 24 – Sep 14 |
| Radishes | — | — | Apr 4 – May 16 | Sep 7 – Sep 28 |
| Cucumbers | Apr 11 – Apr 18 | May 23 – May 30 | May 16 – May 30 | Aug 3 – Aug 17 |
| Zucchini & Summer Squash | Apr 11 – Apr 18 | — | May 16 – May 30 | Aug 10 – Aug 24 |
| Winter Squash & Pumpkins | Apr 11 – Apr 18 | — | May 16 – May 30 | — |
| Melons & Watermelon | Apr 11 – Apr 18 | May 23 – Jun 6 | — | — |
| Carrots | — | — | Apr 18 – May 16 | Jul 27 – Aug 10 |
| Beets | — | — | Apr 18 – May 16 | Aug 10 – Aug 24 |
| Potatoes | — | — | Apr 18 – May 9 | — |
| Swiss Chard | — | — | Apr 25 – May 23 | Aug 10 – Aug 24 |
| Cilantro | — | — | Apr 25 – May 16 | Aug 24 – Sep 14 |
| Green Beans | — | — | May 16 – Jun 6 | Aug 3 – Aug 17 |
| Sweet Corn | — | — | May 16 – May 30 | — |
| Sweet Potatoes | — | May 23 – Jun 13 | — | — |
| Garlic | — | — | — | Oct 5 – Nov 9 |
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 Williams 35 Nnw, AZ weather station, 28 km away (elevation 5,991 ft (1,826 m)).
Frost dates near Williams
- Parks Jun 21 · Sep 17
- Grand Canyon Jun 17 · Sep 24
- Bellemont Jun 21 · Sep 17
- Ash Fork May 22 · Oct 5
- Gray Mountain Apr 7 · Nov 3
- Flagstaff Jun 4 · Sep 28
- Paulden May 24 · Oct 7
- North Rim Jun 3 · Sep 27
- Seligman May 10 · Oct 15
- Cameron Apr 16 · Oct 28
Frequently asked questions
When is the last frost in Williams, AZ?
The median last spring frost in Williams, AZ is May 9. There is still about a 10% chance of frost after May 27, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Williams, AZ?
The median first fall frost is October 19, with about a 10% chance of frost before October 3.
How long is the growing season in Williams, AZ?
About 163 days between the median last spring frost and first fall frost.
What planting zone is Williams, AZ?
Williams, AZ is in USDA hardiness zone 7a.