Koyuk, AK frost dates
Last spring frostMay 25median date
First fall frostSep 3median date
Growing season101 daysfrost-free
Hardiness zone3bZone 3b
How Koyuk compares
- In 8 years out of 10, the last spring frost in Koyuk falls between May 10 and June 11, a 32-day window. The first fall frost falls between August 18 and September 21.
- The median last frost is 4 days later than the Alaska median of May 21.
- Its 101-day growing season is longer than 19% of the 165 Alaska places with a regular frost season (state median 124 days).
- The last frost is 8 days later than the zone 3b median of May 17. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 3b chart.
- The weather station records an average of 234 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 10 |
| 50% (median) | May 25 |
| 10% (safe for tender plants) | June 11 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 18 |
| 50% (median) | September 3 |
| 90% (late) | September 21 |
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 Koyuk, AK
Koyuk, AK frost dates — last frost May 25, first frost Sep 3, zone 3b. whenisthelastfrost.com
Crop
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Start indoors: Mar 2 to Mar 16Transplant outside: Apr 27 to May 11
Start indoors: Mar 16 to Mar 30Transplant outside: Jun 8 to Jun 22
Start indoors: Mar 16 to Mar 30Transplant outside: Jun 8 to Jun 22
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 1 to Jun 15
Start indoors: Mar 30 to Apr 13Transplant outside: May 4 to May 18Sow outdoors: Apr 27 to Jun 1Plant for fall: Jul 9 to Aug 6
Start indoors: Mar 30 to Apr 13Transplant outside: Apr 27 to May 11Sow outdoors: Apr 27 to May 11Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 30 to Apr 13Transplant outside: May 11 to May 25
Start indoors: Mar 30 to Apr 13Transplant outside: May 4 to May 18
Start indoors: Mar 30 to Apr 13Transplant outside: May 11 to May 25
Start indoors: Apr 13 to Apr 27Transplant outside: Jun 15 to Jun 29Sow outdoors: Jun 15 to Jun 29
Start indoors: Apr 13 to Apr 27Transplant outside: Jun 1 to Jun 15
Sow outdoors: Apr 13 to May 4Plant for fall: Jun 11 to Jul 2
Sow outdoors: Apr 13 to May 4Plant for fall: Jul 9 to Jul 30
Sow outdoors: Apr 20 to Jun 1Plant for fall: Jul 23 to Aug 13
Start indoors: Apr 27 to May 4Transplant outside: Jun 8 to Jun 15Sow outdoors: Jun 1 to Jun 15
Start indoors: Apr 27 to May 4Sow outdoors: Jun 1 to Jun 15
Start indoors: Apr 27 to May 4Sow outdoors: Jun 1 to Jun 15
Start indoors: Apr 27 to May 4Transplant outside: Jun 8 to Jun 22
Sow outdoors: May 4 to Jun 1
Sow outdoors: May 4 to Jun 1Plant for fall: Jun 25 to Jul 9
Sow outdoors: May 4 to May 25
Sow outdoors: May 11 to Jun 8Plant for fall: Jun 25 to Jul 9
Sow outdoors: May 11 to Jun 1Plant for fall: Jul 9 to Jul 30
Sow outdoors: Jun 1 to Jun 22
Sow outdoors: Jun 1 to Jun 15
Transplant outside: Jun 8 to Jun 29
Plant for fall: Aug 20 to Sep 24
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Koyuk, AK
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 2 – Mar 16 | Apr 27 – May 11 | — | — |
| Peppers | Mar 16 – Mar 30 | Jun 8 – Jun 22 | — | — |
| Eggplant | Mar 16 – Mar 30 | Jun 8 – Jun 22 | — | — |
| Tomatoes | Mar 30 – Apr 13 | Jun 1 – Jun 15 | — | — |
| Lettuce | Mar 30 – Apr 13 | May 4 – May 18 | Apr 27 – Jun 1 | Jul 9 – Aug 6 |
| Kale | Mar 30 – Apr 13 | Apr 27 – May 11 | Apr 27 – May 11 | Jun 25 – Jul 16 |
| Broccoli | Mar 30 – Apr 13 | May 11 – May 25 | — | — |
| Cabbage | Mar 30 – Apr 13 | May 4 – May 18 | — | — |
| Cauliflower | Mar 30 – Apr 13 | May 11 – May 25 | — | — |
| Okra | Apr 13 – Apr 27 | Jun 15 – Jun 29 | Jun 15 – Jun 29 | — |
| Basil | Apr 13 – Apr 27 | Jun 1 – Jun 15 | — | — |
| Peas | — | — | Apr 13 – May 4 | Jun 11 – Jul 2 |
| Spinach | — | — | Apr 13 – May 4 | Jul 9 – Jul 30 |
| Radishes | — | — | Apr 20 – Jun 1 | Jul 23 – Aug 13 |
| Cucumbers | Apr 27 – May 4 | Jun 8 – Jun 15 | Jun 1 – Jun 15 | — |
| Zucchini & Summer Squash | Apr 27 – May 4 | — | Jun 1 – Jun 15 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 101 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | Apr 27 – May 4 | — | Jun 1 – Jun 15 | — |
| Melons & Watermelon | Apr 27 – May 4 | Jun 8 – Jun 22 | — | — |
| Carrots | — | — | May 4 – Jun 1 | — |
| Beets | — | — | May 4 – Jun 1 | Jun 25 – Jul 9 |
| Potatoes | — | — | May 4 – May 25 | — |
| Swiss Chard | — | — | May 11 – Jun 8 | Jun 25 – Jul 9 |
| Cilantro | — | — | May 11 – Jun 1 | Jul 9 – Jul 30 |
| Green Beans | — | — | Jun 1 – Jun 22 | — |
| Sweet Corn | — | — | Jun 1 – Jun 15 | — |
| Sweet Potatoes Warning: Your frost-free season is about 101 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 8 – Jun 29 | — | — |
| Garlic | — | — | — | Aug 20 – Sep 24 |
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 Kaltag Ap, AK weather station, 133 km away (elevation 180 ft (55 m)). That is far enough away that your dates may differ, especially if your elevation is different.
Frost dates near Koyuk
- Shaktoolik May 25 · Sep 3
- White Mountain Jun 5 · Sep 3
- Buckland frost any month
- Unalakleet May 25 · Sep 3
- Kaltag May 25 · Sep 3
- Deering frost any month
- Nulato May 25 · Sep 3
- Koyukuk May 18 · Sep 8
- Selawik Jun 5 · Sep 24
- Galena May 18 · Sep 8
Frequently asked questions
When is the last frost in Koyuk, AK?
The median last spring frost in Koyuk, AK is May 25. There is still about a 10% chance of frost after June 11, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Koyuk, AK?
The median first fall frost is September 3, with about a 10% chance of frost before August 18.
How long is the growing season in Koyuk, AK?
About 101 days between the median last spring frost and first fall frost.
What planting zone is Koyuk, AK?
Koyuk, AK is in USDA hardiness zone 3b.