Kenai, AK frost dates
Last spring frostMay 24median date
First fall frostSep 12median date
Growing season111 daysfrost-free
Hardiness zone5aZone 5a
How Kenai compares
- In 8 years out of 10, the last spring frost in Kenai falls between May 8 and June 4, a 27-day window. The first fall frost falls between August 29 and September 27.
- The median last frost is 3 days later than the Alaska median of May 21.
- Its 111-day growing season is longer than 30% of the 165 Alaska places with a regular frost season (state median 124 days).
- The last frost is 21 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 197 nights a year at or below 32°F.
- Compared with Anchorage, AK, 98 km away, the last frost here is 4 days earlier than there and the growing season is 4 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 8 |
| 50% (median) | May 24 |
| 10% (safe for tender plants) | June 4 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 29 |
| 50% (median) | September 12 |
| 90% (late) | September 27 |
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 Kenai, AK
Kenai, AK frost dates — last frost May 24, first frost Sep 12, zone 5a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 26 to May 10
Start indoors: Mar 15 to Mar 29Transplant outside: Jun 7 to Jun 21
Start indoors: Mar 15 to Mar 29Transplant outside: Jun 7 to Jun 21
Start indoors: Mar 29 to Apr 12Transplant outside: May 31 to Jun 14
Start indoors: Mar 29 to Apr 12Transplant outside: May 3 to May 17Sow outdoors: Apr 26 to May 31Plant for fall: Jul 18 to Aug 15
Start indoors: Mar 29 to Apr 12Transplant outside: Apr 26 to May 10Sow outdoors: Apr 26 to May 10Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 29 to Apr 12Transplant outside: May 10 to May 24
Start indoors: Mar 29 to Apr 12Transplant outside: May 3 to May 17
Start indoors: Mar 29 to Apr 12Transplant outside: May 10 to May 24
Start indoors: Apr 12 to Apr 26Transplant outside: Jun 14 to Jun 28Sow outdoors: Jun 14 to Jun 28
Start indoors: Apr 12 to Apr 26Transplant outside: May 31 to Jun 14
Sow outdoors: Apr 12 to May 3Plant for fall: Jun 20 to Jul 11
Sow outdoors: Apr 12 to May 3Plant for fall: Jul 18 to Aug 8
Sow outdoors: Apr 19 to May 31Plant for fall: Aug 1 to Aug 22
Start indoors: Apr 26 to May 3Transplant outside: Jun 7 to Jun 14Sow outdoors: May 31 to Jun 14
Start indoors: Apr 26 to May 3Sow outdoors: May 31 to Jun 14Plant for fall: Jul 4 to Jul 18
Start indoors: Apr 26 to May 3Sow outdoors: May 31 to Jun 14
Start indoors: Apr 26 to May 3Transplant outside: Jun 7 to Jun 21
Sow outdoors: May 3 to May 31Plant for fall: Jun 20 to Jul 4
Sow outdoors: May 3 to May 31Plant for fall: Jul 4 to Jul 18
Sow outdoors: May 3 to May 24
Sow outdoors: May 10 to Jun 7Plant for fall: Jul 4 to Jul 18
Sow outdoors: May 10 to May 31Plant for fall: Jul 18 to Aug 8
Sow outdoors: May 31 to Jun 21
Sow outdoors: May 31 to Jun 14
Transplant outside: Jun 7 to Jun 28
Plant for fall: Aug 29 to Oct 3
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Kenai, AK
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 1 – Mar 15 | Apr 26 – May 10 | — | — |
| Peppers | Mar 15 – Mar 29 | Jun 7 – Jun 21 | — | — |
| Eggplant | Mar 15 – Mar 29 | Jun 7 – Jun 21 | — | — |
| Tomatoes | Mar 29 – Apr 12 | May 31 – Jun 14 | — | — |
| Lettuce | Mar 29 – Apr 12 | May 3 – May 17 | Apr 26 – May 31 | Jul 18 – Aug 15 |
| Kale | Mar 29 – Apr 12 | Apr 26 – May 10 | Apr 26 – May 10 | Jul 4 – Jul 25 |
| Broccoli | Mar 29 – Apr 12 | May 10 – May 24 | — | — |
| Cabbage | Mar 29 – Apr 12 | May 3 – May 17 | — | — |
| Cauliflower | Mar 29 – Apr 12 | May 10 – May 24 | — | — |
| Okra | Apr 12 – Apr 26 | Jun 14 – Jun 28 | Jun 14 – Jun 28 | — |
| Basil | Apr 12 – Apr 26 | May 31 – Jun 14 | — | — |
| Peas | — | — | Apr 12 – May 3 | Jun 20 – Jul 11 |
| Spinach | — | — | Apr 12 – May 3 | Jul 18 – Aug 8 |
| Radishes | — | — | Apr 19 – May 31 | Aug 1 – Aug 22 |
| Cucumbers | Apr 26 – May 3 | Jun 7 – Jun 14 | May 31 – Jun 14 | — |
| Zucchini & Summer Squash | Apr 26 – May 3 | — | May 31 – Jun 14 | Jul 4 – Jul 18 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 111 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | Apr 26 – May 3 | — | May 31 – Jun 14 | — |
| Melons & Watermelon | Apr 26 – May 3 | Jun 7 – Jun 21 | — | — |
| Carrots | — | — | May 3 – May 31 | Jun 20 – Jul 4 |
| Beets | — | — | May 3 – May 31 | Jul 4 – Jul 18 |
| Potatoes | — | — | May 3 – May 24 | — |
| Swiss Chard | — | — | May 10 – Jun 7 | Jul 4 – Jul 18 |
| Cilantro | — | — | May 10 – May 31 | Jul 18 – Aug 8 |
| Green Beans | — | — | May 31 – Jun 21 | — |
| Sweet Corn | — | — | May 31 – Jun 14 | — |
| Sweet Potatoes Warning: Your frost-free season is about 111 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 7 – Jun 28 | — | — |
| Garlic | — | — | — | Aug 29 – Oct 3 |
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 Kenai Muni Ap, AK weather station, 4 km away (elevation 92 ft (28 m)).
Frost dates near Kenai
- Nikiski May 18 · Sep 22
- Soldotna Jun 11 · Sep 1
- Sterling May 20 · Sep 21
- Kasilof Jun 11 · Sep 1
- Clam Gulch Jun 11 · Sep 1
- Tyonek May 18 · Sep 22
- Ninilchik May 16 · Sep 30
- Cooper Landing Jun 12 · Sep 1
- Anchor Point May 16 · Sep 30
- Anchorage May 28 · Sep 12
Frequently asked questions
When is the last frost in Kenai, AK?
The median last spring frost in Kenai, AK is May 24. There is still about a 10% chance of frost after June 4, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Kenai, AK?
The median first fall frost is September 12, with about a 10% chance of frost before August 29.
How long is the growing season in Kenai, AK?
About 111 days between the median last spring frost and first fall frost.
What planting zone is Kenai, AK?
Kenai, AK is in USDA hardiness zone 5a.