Frost dates for Williams, 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 9
typical year
Safe to plant
May 27
frost is over in 9 of 10 years
First fall frost
October 19
typical year
Growing season
161 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 11 – 25 | – |
| Spinach | – | Mar 28 – Apr 18 | Aug 24 – Sep 7 |
| Lettuce | – | Apr 11 – May 2 | Aug 24 – Sep 7 |
| Radishes | – | Apr 11 – May 23 | Sep 7 – 21 |
| Onions | – | Apr 11 – 25 | – |
| Potatoes | – | Apr 18 – May 2 | – |
| Carrots | – | Apr 18 – May 9 | Jul 27 – Aug 10 |
| Beets | – | Apr 11 – 25 | Aug 10 – 24 |
| Kale | Feb 28 – Mar 14 | Apr 11 – 25 | Aug 10 – 24 |
| Broccoli | Feb 28 – Mar 14 | Apr 25 – May 9 | Aug 10 – 24 |
| Cabbage | Feb 14 – 28 | Apr 11 – 25 | Aug 10 – 24 |
| Garlic | – | – | Sep 7 – 28 |
| Warm-season crops | |||
| Tomatoes | Apr 1 – 15 | May 27 – Jun 10 | – |
| Peppers | Mar 25 – Apr 8 | Jun 3 – 17 | – |
| Cucumbers | – | May 27 – Jun 17 | – |
| Zucchini | – | May 27 – Jun 24 | – |
| Pumpkins | – | May 27 – Jun 17 | – |
| Green beans | – | May 27 – Aug 10 | – |
| Sweet corn | – | May 27 – Jun 24 | – |
| Basil | Apr 22 – May 6 | Jun 3 – 10 | – |
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 27 | May 9 | April 24 |
| Fall frost before | October 3 | October 19 | November 3 |
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 24 (May 14 in a late year), and the first one in fall around October 31.
Where these dates come from
NOAA weather station WILLIAMS 35 NNW, AZ US (USW00053155), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 38 miles:
86435
1 of these zip codes are more than 30 miles from the station, so their real frost dates may differ by a week or more.
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.