Frost dates for Saint Johns, 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
May 2
typical year
Safe to plant
May 17
frost is over in 9 of 10 years
First fall frost
October 14
typical year
Growing season
164 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 | – | Apr 4 – 18 | – |
| Spinach | – | Mar 21 – Apr 11 | Aug 19 – Sep 2 |
| Lettuce | – | Apr 4 – 25 | Aug 19 – Sep 2 |
| Radishes | – | Apr 4 – May 16 | Sep 2 – 16 |
| Onions | – | Apr 4 – 18 | – |
| Potatoes | – | Apr 11 – 25 | – |
| Carrots | – | Apr 11 – May 2 | Jul 22 – Aug 5 |
| Beets | – | Apr 4 – 18 | Aug 5 – 19 |
| Kale | Feb 21 – Mar 7 | Apr 4 – 18 | Aug 5 – 19 |
| Broccoli | Feb 21 – Mar 7 | Apr 18 – May 2 | Aug 5 – 19 |
| Cabbage | Feb 7 – 21 | Apr 4 – 18 | Aug 5 – 19 |
| Garlic | – | – | Sep 2 – 23 |
| 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 5 | – |
| 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 | May 2 | April 18 |
| Fall frost before | October 3 | October 14 | October 27 |
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 19 (May 5 in a late year), and the first one in fall around October 23.
Where these dates come from
NOAA weather station SAINT JOHNS, AZ US (USC00027435), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 16 miles:
85924
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.