Frost dates for Unalaska, AK
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 6
typical year
Safe to plant
May 22
frost is over in 9 of 10 years
First fall frost
October 18
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 8 – 22 | – |
| Spinach | – | Mar 25 – Apr 15 | Aug 23 – Sep 6 |
| Lettuce | – | Apr 8 – 29 | Aug 23 – Sep 6 |
| Radishes | – | Apr 8 – May 20 | Sep 6 – 20 |
| Onions | – | Apr 8 – 22 | – |
| Potatoes | – | Apr 15 – 29 | – |
| Carrots | – | Apr 15 – May 6 | Jul 26 – Aug 9 |
| Beets | – | Apr 8 – 22 | Aug 9 – 23 |
| Kale | Feb 25 – Mar 11 | Apr 8 – 22 | Aug 9 – 23 |
| Broccoli | Feb 25 – Mar 11 | Apr 22 – May 6 | Aug 9 – 23 |
| Cabbage | Feb 11 – 25 | Apr 8 – 22 | Aug 9 – 23 |
| Garlic | – | – | Sep 6 – 27 |
| Warm-season crops | |||
| Tomatoes | Mar 27 – Apr 10 | May 22 – Jun 5 | – |
| Peppers | Mar 20 – Apr 3 | May 29 – Jun 12 | – |
| Cucumbers | – | May 22 – Jun 12 | – |
| Zucchini | – | May 22 – Jun 19 | – |
| Pumpkins | – | May 22 – Jun 12 | – |
| Green beans | – | May 22 – Aug 9 | – |
| Sweet corn | – | May 22 – Jun 19 | – |
| Basil | Apr 17 – May 1 | May 29 – Jun 5 | – |
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 22 | May 6 | April 23 |
| Fall frost before | September 20 | October 18 | November 5 |
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 November 4.
Towns that use these dates
This is the nearest NOAA station with frost records for 3 towns.
Unalaska, Akutan, Atka
Where these dates come from
NOAA weather station DUTCH HARBOR, AK US (USC00502587), 1991–2020 climate normals. It's the nearest station for 5 zip codes, all within 339 miles:
99547, 99553, 99638, 99685, 99692
3 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.