Frost dates for 86005 — Flagstaff, AZ
Last spring frostJun 4median date
First fall frostSep 28median date
Growing season116 daysfrost-free
Hardiness zone6aZone 6a
How Flagstaff compares
- In 8 years out of 10, the last spring frost in Flagstaff falls between May 21 and June 19, a 29-day window. The first fall frost falls between September 16 and October 9.
- The median last frost is 49 days later than the Arizona median of Apr 16.
- Its 116-day growing season is longer than 4% of the 193 Arizona places with a regular frost season (state median 197 days).
- The last frost is 36 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 202 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 21 |
| 50% (median) | June 4 |
| 10% (safe for tender plants) | June 19 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 16 |
| 50% (median) | September 28 |
| 90% (late) | October 9 |
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 Flagstaff, AZ
Frost dates for 86005 — Flagstaff, AZ — last frost Jun 4, first frost Sep 28, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Mar 12 to Mar 26Transplant outside: May 7 to May 21
Start indoors: Mar 26 to Apr 9Transplant outside: Jun 18 to Jul 2
Start indoors: Mar 26 to Apr 9Transplant outside: Jun 18 to Jul 2
Start indoors: Apr 9 to Apr 23Transplant outside: Jun 11 to Jun 25
Start indoors: Apr 9 to Apr 23Transplant outside: May 14 to May 28Sow outdoors: May 7 to Jun 11Plant for fall: Aug 3 to Aug 31
Start indoors: Apr 9 to Apr 23Transplant outside: May 7 to May 21Sow outdoors: May 7 to May 21Plant for fall: Jul 20 to Aug 10
Start indoors: Apr 9 to Apr 23Transplant outside: May 21 to Jun 4Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 9 to Apr 23Transplant outside: May 14 to May 28Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 9 to Apr 23Transplant outside: May 21 to Jun 4Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 23 to May 7Transplant outside: Jun 25 to Jul 9Sow outdoors: Jun 25 to Jul 9
Start indoors: Apr 23 to May 7Transplant outside: Jun 11 to Jun 25
Sow outdoors: Apr 23 to May 14Plant for fall: Jul 6 to Jul 27
Sow outdoors: Apr 23 to May 14Plant for fall: Aug 3 to Aug 24
Sow outdoors: Apr 30 to Jun 11Plant for fall: Aug 17 to Sep 7
Start indoors: May 7 to May 14Transplant outside: Jun 18 to Jun 25Sow outdoors: Jun 11 to Jun 25Plant for fall: Jul 13 to Jul 27
Start indoors: May 7 to May 14Sow outdoors: Jun 11 to Jun 25Plant for fall: Jul 20 to Aug 3
Start indoors: May 7 to May 14Sow outdoors: Jun 11 to Jun 25
Start indoors: May 7 to May 14Transplant outside: Jun 18 to Jul 2
Sow outdoors: May 14 to Jun 11Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 14 to Jun 11Plant for fall: Jul 20 to Aug 3
Sow outdoors: May 14 to Jun 4
Sow outdoors: May 21 to Jun 18Plant for fall: Jul 20 to Aug 3
Sow outdoors: May 21 to Jun 11Plant for fall: Aug 3 to Aug 24
Sow outdoors: Jun 11 to Jul 2
Sow outdoors: Jun 11 to Jun 25
Transplant outside: Jun 18 to Jul 9
Plant for fall: Sep 14 to Oct 19
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Flagstaff, AZ
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 12 – Mar 26 | May 7 – May 21 | — | — |
| Peppers | Mar 26 – Apr 9 | Jun 18 – Jul 2 | — | — |
| Eggplant | Mar 26 – Apr 9 | Jun 18 – Jul 2 | — | — |
| Tomatoes | Apr 9 – Apr 23 | Jun 11 – Jun 25 | — | — |
| Lettuce | Apr 9 – Apr 23 | May 14 – May 28 | May 7 – Jun 11 | Aug 3 – Aug 31 |
| Kale | Apr 9 – Apr 23 | May 7 – May 21 | May 7 – May 21 | Jul 20 – Aug 10 |
| Broccoli | Apr 9 – Apr 23 | May 21 – Jun 4 | — | Jun 22 – Jul 13 |
| Cabbage | Apr 9 – Apr 23 | May 14 – May 28 | — | Jun 22 – Jul 13 |
| Cauliflower | Apr 9 – Apr 23 | May 21 – Jun 4 | — | Jun 22 – Jul 13 |
| Okra | Apr 23 – May 7 | Jun 25 – Jul 9 | Jun 25 – Jul 9 | — |
| Basil | Apr 23 – May 7 | Jun 11 – Jun 25 | — | — |
| Peas | — | — | Apr 23 – May 14 | Jul 6 – Jul 27 |
| Spinach | — | — | Apr 23 – May 14 | Aug 3 – Aug 24 |
| Radishes | — | — | Apr 30 – Jun 11 | Aug 17 – Sep 7 |
| Cucumbers | May 7 – May 14 | Jun 18 – Jun 25 | Jun 11 – Jun 25 | Jul 13 – Jul 27 |
| Zucchini & Summer Squash | May 7 – May 14 | — | Jun 11 – Jun 25 | Jul 20 – Aug 3 |
| Winter Squash & Pumpkins | May 7 – May 14 | — | Jun 11 – Jun 25 | — |
| Melons & Watermelon | May 7 – May 14 | Jun 18 – Jul 2 | — | — |
| Carrots | — | — | May 14 – Jun 11 | Jul 6 – Jul 20 |
| Beets | — | — | May 14 – Jun 11 | Jul 20 – Aug 3 |
| Potatoes | — | — | May 14 – Jun 4 | — |
| Swiss Chard | — | — | May 21 – Jun 18 | Jul 20 – Aug 3 |
| Cilantro | — | — | May 21 – Jun 11 | Aug 3 – Aug 24 |
| Green Beans | — | — | Jun 11 – Jul 2 | — |
| Sweet Corn | — | — | Jun 11 – Jun 25 | — |
| Sweet Potatoes | — | Jun 18 – Jul 9 | — | — |
| 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 Flagstaff Pulliam Ap, AZ weather station, 2 km away (elevation 7,005 ft (2,135 m)).
ZIP codes in Flagstaff: 86001 86002 86003 86004 86005 86011
Frost dates near Flagstaff
- Bellemont Jun 21 · Sep 17
- Munds Park Jun 10 · Sep 27
- Parks Jun 21 · Sep 17
- Mormon Lake Jun 10 · Sep 27
- Sedona Apr 1 · Nov 17
- Cornville Mar 30 · Nov 10
- Clarkdale Mar 30 · Nov 10
- Lake Montezuma Apr 16 · Oct 30
Frequently asked questions
When is the last frost in Flagstaff, AZ?
The median last spring frost in Flagstaff, AZ is June 4. There is still about a 10% chance of frost after June 19, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Flagstaff, 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 Flagstaff, AZ?
About 116 days between the median last spring frost and first fall frost.
What planting zone is Flagstaff, AZ?
Flagstaff, AZ is in USDA hardiness zone 6a.