Denali National Park, AK frost dates
Last spring frostMay 25median date
First fall frostSep 8median date
Growing season106 daysfrost-free
Hardiness zone3bZone 3b
How Denali National Park compares
- In 8 years out of 10, the last spring frost in Denali National Park falls between May 13 and June 3, a 21-day window. The first fall frost falls between August 26 and September 20.
- The median last frost is 4 days later than the Alaska median of May 21.
- Its 106-day growing season is longer than 27% 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 230 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 13 |
| 50% (median) | May 25 |
| 10% (safe for tender plants) | June 3 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 26 |
| 50% (median) | September 8 |
| 90% (late) | September 20 |
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 Denali National Park, AK
Denali National Park, AK frost dates — last frost May 25, first frost Sep 8, zone 3b. whenisthelastfrost.com
Crop
JFMAMJJASOND
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 14 to Aug 11
Start indoors: Mar 30 to Apr 13Transplant outside: Apr 27 to May 11Sow outdoors: Apr 27 to May 11Plant for fall: Jun 30 to Jul 21
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 16 to Jul 7
Sow outdoors: Apr 13 to May 4Plant for fall: Jul 14 to Aug 4
Sow outdoors: Apr 20 to Jun 1Plant for fall: Jul 28 to Aug 18
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 15Plant for fall: Jun 30 to Jul 14
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 1Plant for fall: Jun 16 to Jun 30
Sow outdoors: May 4 to Jun 1Plant for fall: Jun 30 to Jul 14
Sow outdoors: May 4 to May 25
Sow outdoors: May 11 to Jun 8Plant for fall: Jun 30 to Jul 14
Sow outdoors: May 11 to Jun 1Plant for fall: Jul 14 to Aug 4
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 25 to Sep 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Denali National Park, 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 14 – Aug 11 |
| Kale | Mar 30 – Apr 13 | Apr 27 – May 11 | Apr 27 – May 11 | Jun 30 – Jul 21 |
| 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 16 – Jul 7 |
| Spinach | — | — | Apr 13 – May 4 | Jul 14 – Aug 4 |
| Radishes | — | — | Apr 20 – Jun 1 | Jul 28 – Aug 18 |
| Cucumbers | Apr 27 – May 4 | Jun 8 – Jun 15 | Jun 1 – Jun 15 | — |
| Zucchini & Summer Squash | Apr 27 – May 4 | — | Jun 1 – Jun 15 | Jun 30 – Jul 14 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 106 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 | Jun 16 – Jun 30 |
| Beets | — | — | May 4 – Jun 1 | Jun 30 – Jul 14 |
| Potatoes | — | — | May 4 – May 25 | — |
| Swiss Chard | — | — | May 11 – Jun 8 | Jun 30 – Jul 14 |
| Cilantro | — | — | May 11 – Jun 1 | Jul 14 – Aug 4 |
| Green Beans | — | — | Jun 1 – Jun 22 | — |
| Sweet Corn | — | — | Jun 1 – Jun 15 | — |
| Sweet Potatoes Warning: Your frost-free season is about 106 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 8 – Jun 29 | — | — |
| Garlic | — | — | — | Aug 25 – Sep 29 |
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 Denali 27 N, AK weather station, 45 km away (elevation 2,224 ft (678 m)). That is far enough away that your dates may differ, especially if your elevation is different.
Frost dates near Denali National Park
- Cantwell frost any month
- Healy May 27 · Sep 1
- Clear May 24 · Sep 4
- Anderson May 24 · Sep 4
- Lake Minchumina May 13 · Sep 17
- Nenana May 15 · Sep 11
- Trapper Creek May 16 · Sep 16
- Talkeetna May 16 · Sep 16
- Manley Hot Springs frost any month
- Minto frost any month
Frequently asked questions
When is the last frost in Denali National Park, AK?
The median last spring frost in Denali National Park, AK is May 25. There is still about a 10% chance of frost after June 3, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Denali National Park, AK?
The median first fall frost is September 8, with about a 10% chance of frost before August 26.
How long is the growing season in Denali National Park, AK?
About 106 days between the median last spring frost and first fall frost.
What planting zone is Denali National Park, AK?
Denali National Park, AK is in USDA hardiness zone 3b.