Frost dates for Kitt Peak, AZ
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 26
typical year
Safe to plant
May 17
frost is over in 9 of 10 years
First fall frost
November 4
typical year
Growing season
195 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Mar 29 – Apr 12 | – |
| Spinach | – | Mar 15 – Apr 5 | Sep 9 – 23 |
| Lettuce | – | Mar 29 – Apr 19 | Sep 9 – 23 |
| Radishes | – | Mar 29 – May 10 | Sep 23 – Oct 7 |
| Onions | – | Mar 29 – Apr 12 | – |
| Potatoes | – | Apr 5 – 19 | – |
| Carrots | – | Apr 5 – 26 | Aug 12 – 26 |
| Beets | – | Mar 29 – Apr 12 | Aug 26 – Sep 9 |
| Kale | Feb 15 – Mar 1 | Mar 29 – Apr 12 | Aug 26 – Sep 9 |
| Broccoli | Feb 15 – Mar 1 | Apr 12 – 26 | Aug 26 – Sep 9 |
| Cabbage | Feb 1 – 15 | Mar 29 – Apr 12 | Aug 26 – Sep 9 |
| Garlic | – | – | Sep 23 – Oct 14 |
| Warm-season crops | |||
| Tomatoes | Mar 22 – Apr 5 | May 17 – 31 | – |
| Peppers | Mar 15 – 29 | May 24 – Jun 7 | – |
| Cucumbers | – | May 17 – Jun 7 | – |
| Zucchini | – | May 17 – Jun 14 | – |
| Pumpkins | – | May 17 – Jun 7 | – |
| Green beans | – | May 17 – Aug 26 | – |
| Sweet corn | – | May 17 – Jun 14 | – |
| Basil | Apr 12 – 26 | May 24 – 31 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | May 17 | April 26 | April 1 |
| Fall frost before | October 18 | November 4 | November 24 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around April 7 (May 5 in a late year), and the first one in fall around November 17.
Where these dates come from
NOAA weather station KITT PEAK, AZ US (USC00024675), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 25 miles:
85634, 85639
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.