Seward, AK frost dates
Last spring frostMay 2median date
First fall frostOct 7median date
Growing season158 daysfrost-free
Hardiness zone5bZone 5b
How Seward compares
- In 8 years out of 10, the last spring frost in Seward falls between April 20 and May 17, a 27-day window. The first fall frost falls between September 28 and October 23.
- The median last frost is 19 days earlier than the Alaska median of May 21.
- Its 158-day growing season is longer than 80% of the 165 Alaska places with a regular frost season (state median 124 days).
- The last frost is typical for zone 5b, where the median is May 1.
- The weather station records an average of 146 nights a year at or below 32°F.
- Compared with Anchorage, AK, 118 km away, the last frost here is 26 days earlier than there and the growing season is 51 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 20 |
| 50% (median) | May 2 |
| 10% (safe for tender plants) | May 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 28 |
| 50% (median) | October 7 |
| 90% (late) | October 23 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Seward, AK
Seward, AK frost dates — last frost May 2, first frost Oct 7, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Feb 7 to Feb 21Transplant outside: Apr 4 to Apr 18
Start indoors: Feb 21 to Mar 7Transplant outside: May 16 to May 30
Start indoors: Feb 21 to Mar 7Transplant outside: May 16 to May 30
Start indoors: Mar 7 to Mar 21Transplant outside: May 9 to May 23
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 11 to Apr 25Sow outdoors: Apr 4 to May 9Plant for fall: Aug 12 to Sep 9
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 4 to Apr 18Sow outdoors: Apr 4 to Apr 18Plant for fall: Jul 29 to Aug 19
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 18 to May 2Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 11 to Apr 25Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 18 to May 2Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 21 to Apr 4Transplant outside: May 23 to Jun 6Sow outdoors: May 23 to Jun 6
Start indoors: Mar 21 to Apr 4Transplant outside: May 9 to May 23
Sow outdoors: Mar 21 to Apr 11Plant for fall: Jul 15 to Aug 5
Sow outdoors: Mar 21 to Apr 11Plant for fall: Aug 12 to Sep 2
Sow outdoors: Mar 28 to May 9Plant for fall: Aug 26 to Sep 16
Start indoors: Apr 4 to Apr 11Transplant outside: May 16 to May 23Sow outdoors: May 9 to May 23Plant for fall: Jul 22 to Aug 5
Start indoors: Apr 4 to Apr 11Sow outdoors: May 9 to May 23Plant for fall: Jul 29 to Aug 12
Start indoors: Apr 4 to Apr 11Sow outdoors: May 9 to May 23
Start indoors: Apr 4 to Apr 11Transplant outside: May 16 to May 30
Sow outdoors: Apr 11 to May 9Plant for fall: Jul 15 to Jul 29
Sow outdoors: Apr 11 to May 9Plant for fall: Jul 29 to Aug 12
Sow outdoors: Apr 11 to May 2
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 29 to Aug 12
Sow outdoors: Apr 18 to May 9Plant for fall: Aug 12 to Sep 2
Sow outdoors: May 9 to May 30Plant for fall: Jul 22 to Aug 5
Sow outdoors: May 9 to May 23
Transplant outside: May 16 to Jun 6
Plant for fall: Sep 23 to Oct 28
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Seward, AK
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 7 – Feb 21 | Apr 4 – Apr 18 | — | — |
| Peppers | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Eggplant | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Tomatoes | Mar 7 – Mar 21 | May 9 – May 23 | — | — |
| Lettuce | Mar 7 – Mar 21 | Apr 11 – Apr 25 | Apr 4 – May 9 | Aug 12 – Sep 9 |
| Kale | Mar 7 – Mar 21 | Apr 4 – Apr 18 | Apr 4 – Apr 18 | Jul 29 – Aug 19 |
| Broccoli | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 1 – Jul 22 |
| Cabbage | Mar 7 – Mar 21 | Apr 11 – Apr 25 | — | Jul 1 – Jul 22 |
| Cauliflower | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 1 – Jul 22 |
| Okra | Mar 21 – Apr 4 | May 23 – Jun 6 | May 23 – Jun 6 | — |
| Basil | Mar 21 – Apr 4 | May 9 – May 23 | — | — |
| Peas | — | — | Mar 21 – Apr 11 | Jul 15 – Aug 5 |
| Spinach | — | — | Mar 21 – Apr 11 | Aug 12 – Sep 2 |
| Radishes | — | — | Mar 28 – May 9 | Aug 26 – Sep 16 |
| Cucumbers | Apr 4 – Apr 11 | May 16 – May 23 | May 9 – May 23 | Jul 22 – Aug 5 |
| Zucchini & Summer Squash | Apr 4 – Apr 11 | — | May 9 – May 23 | Jul 29 – Aug 12 |
| Winter Squash & Pumpkins | Apr 4 – Apr 11 | — | May 9 – May 23 | — |
| Melons & Watermelon | Apr 4 – Apr 11 | May 16 – May 30 | — | — |
| Carrots | — | — | Apr 11 – May 9 | Jul 15 – Jul 29 |
| Beets | — | — | Apr 11 – May 9 | Jul 29 – Aug 12 |
| Potatoes | — | — | Apr 11 – May 2 | — |
| Swiss Chard | — | — | Apr 18 – May 16 | Jul 29 – Aug 12 |
| Cilantro | — | — | Apr 18 – May 9 | Aug 12 – Sep 2 |
| Green Beans | — | — | May 9 – May 30 | Jul 22 – Aug 5 |
| Sweet Corn | — | — | May 9 – May 23 | — |
| Sweet Potatoes | — | May 16 – Jun 6 | — | — |
| Garlic | — | — | — | Sep 23 – Oct 28 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Seward Ap, AK weather station, about 1 km away (elevation 23 ft (7 m)).
Frost dates near Seward
- Cooper Landing Jun 12 · Sep 1
- Moose Pass May 31 · Sep 8
- Whittier Apr 25 · Oct 14
- Hope May 18 · Sep 24
- Sterling May 20 · Sep 21
- Girdwood May 8 · Sep 29
- Soldotna Jun 11 · Sep 1
- Kasilof Jun 11 · Sep 1
- Indian May 18 · Sep 23
- Clam Gulch Jun 11 · Sep 1
Frequently asked questions
When is the last frost in Seward, AK?
The median last spring frost in Seward, AK is May 2. There is still about a 10% chance of frost after May 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Seward, AK?
The median first fall frost is October 7, with about a 10% chance of frost before September 28.
How long is the growing season in Seward, AK?
About 158 days between the median last spring frost and first fall frost.
What planting zone is Seward, AK?
Seward, AK is in USDA hardiness zone 5b.