Frost dates for Tucson U Of A #1, 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
February 11
typical year
Safe to plant
March 7
frost is over in 9 of 10 years
First fall frost
December 2
typical year
Growing season
293 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 | – | Jan 14 – 28 | – |
| Spinach | – | Dec 31 – Jan 21 | Oct 7 – 21 |
| Lettuce | – | Jan 14 – Feb 4 | Oct 7 – 21 |
| Radishes | – | Jan 14 – Feb 25 | Oct 21 – Nov 4 |
| Onions | – | Jan 14 – 28 | – |
| Potatoes | – | Jan 21 – Feb 4 | – |
| Carrots | – | Jan 21 – Feb 11 | Sep 9 – 23 |
| Beets | – | Jan 14 – 28 | Sep 23 – Oct 7 |
| Kale | Dec 3 – 17 | Jan 14 – 28 | Sep 23 – Oct 7 |
| Broccoli | Dec 3 – 17 | Jan 28 – Feb 11 | Sep 23 – Oct 7 |
| Cabbage | Nov 19 – Dec 3 | Jan 14 – 28 | Sep 23 – Oct 7 |
| Garlic | – | – | Oct 21 – Nov 11 |
| Warm-season crops | |||
| Tomatoes | Jan 10 – 24 | Mar 7 – 21 | – |
| Peppers | Jan 3 – 17 | Mar 14 – 28 | – |
| Cucumbers | – | Mar 7 – 28 | – |
| Zucchini | – | Mar 7 – Apr 4 | – |
| Pumpkins | – | Mar 7 – 28 | – |
| Green beans | – | Mar 7 – Sep 23 | – |
| Sweet corn | – | Mar 7 – Apr 4 | – |
| Basil | Jan 31 – Feb 14 | Mar 14 – 21 | – |
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 | March 7 | February 11 | January 16 |
| Fall frost before | November 16 | December 2 | December 20 |
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 January 18 (February 17 in a late year), and the first one in fall around December 15.
Where these dates come from
NOAA weather station TUCSON U OF A #1, AZ US (USC00028817), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 3 miles:
85705, 85745
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.