When to plant in Flagstaff, AZ
USDA Zone 6aFlagstaff, Arizona frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
A ~116-day frost-free window makes Flagstaff a short-season garden: choose early varieties and start long-season crops indoors well ahead of the last frost. Zone 6a means Flagstaff sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
FLAGSTAFF PULLIAM AP · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Flagstaff’s own odds, recorded at FLAGSTAFF PULLIAM AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jul 1 | Jun 16 | Jun 3 | Sep 6 | Sep 19 | Sep 28 |
| 32°F | Jun 19 | Jun 4 | May 21 | Sep 16 | Sep 28 | Oct 9 |
| 28°F | Jun 6 | May 20 | May 1 | Sep 28 | Oct 9 | Oct 22 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Flagstaff, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 10 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Flagstaff planting FAQ
When is the last spring frost in Flagstaff, AZ?
On average, the last spring frost in Flagstaff is around June 4 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Flagstaff, AZ?
The first fall frost in Flagstaff typically arrives around September 28 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Flagstaff in?
Flagstaff is in USDA hardiness zone 6a. In zone 6a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Flagstaff?
There are roughly 116 frost-free days in Flagstaff (a short growing season), running from the average last frost around June 4 to the first fall frost near September 28.
When should I plant tomatoes in Flagstaff?
In Flagstaff, start tomato seeds indoors around April 9–April 23, then transplant seedlings outdoors around June 11 once the danger of frost has passed.
Never miss a window in Flagstaff
An email when it’s time to start seeds, transplant, and sow — timed to Flagstaff’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Cottonwood · 59 km
- Verde Village · 63 km
- Camp Verde · 72 km
- Chino Valley · 87 km
- Prescott Valley · 91 km
- Prescott · 100 km
- Payson · 108 km
- New River · 151 km
Frost dates recorded at FLAGSTAFF PULLIAM AP, 6 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Flagstaff, AZ — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00003103. Retrieved from https://blissgarden.com/arizona/flagstaff.