Willow, AK frost dates
Last spring frostMay 15median date
First fall frostSep 18median date
Growing season126 daysfrost-free
Hardiness zone3bZone 3b
How Willow compares
- In 8 years out of 10, the last spring frost in Willow falls between May 3 and May 28, a 25-day window. The first fall frost falls between September 4 and September 28.
- The median last frost is 6 days earlier than the Alaska median of May 21.
- Its 126-day growing season is longer than 61% of the 165 Alaska places with a regular frost season (state median 124 days).
- The last frost is typical for zone 3b, where the median is May 17.
- The weather station records an average of 219 nights a year at or below 32°F.
- Compared with Anchorage, AK, 81 km away, the last frost here is 13 days earlier than there and the growing season is 19 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 3 |
| 50% (median) | May 15 |
| 10% (safe for tender plants) | May 28 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 4 |
| 50% (median) | September 18 |
| 90% (late) | September 28 |
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 Willow, AK
Willow, AK frost dates — last frost May 15, first frost Sep 18, zone 3b. whenisthelastfrost.com
Crop
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Start indoors: Feb 20 to Mar 6Transplant outside: Apr 17 to May 1
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Sow outdoors: Apr 17 to May 22Plant for fall: Jul 24 to Aug 21
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 17 to May 1Sow outdoors: Apr 17 to May 1Plant for fall: Jul 10 to Jul 31
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jun 12 to Jul 3
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Plant for fall: Jun 12 to Jul 3
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jun 12 to Jul 3
Start indoors: Apr 3 to Apr 17Transplant outside: Jun 5 to Jun 19Sow outdoors: Jun 5 to Jun 19
Start indoors: Apr 3 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 3 to Apr 24Plant for fall: Jun 26 to Jul 17
Sow outdoors: Apr 3 to Apr 24Plant for fall: Jul 24 to Aug 14
Sow outdoors: Apr 10 to May 22Plant for fall: Aug 7 to Aug 28
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 5Sow outdoors: May 22 to Jun 5Plant for fall: Jul 3 to Jul 17
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5Plant for fall: Jul 10 to Jul 24
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 12
Sow outdoors: Apr 24 to May 22Plant for fall: Jun 26 to Jul 10
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 10 to Jul 24
Sow outdoors: Apr 24 to May 15
Sow outdoors: May 1 to May 29Plant for fall: Jul 10 to Jul 24
Sow outdoors: May 1 to May 22Plant for fall: Jul 24 to Aug 14
Sow outdoors: May 22 to Jun 12Plant for fall: Jul 3 to Jul 17
Sow outdoors: May 22 to Jun 5
Transplant outside: May 29 to Jun 19
Plant for fall: Sep 4 to Oct 9
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Willow, AK
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 20 – Mar 6 | Apr 17 – May 1 | — | — |
| Peppers | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Eggplant | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Tomatoes | Mar 20 – Apr 3 | May 22 – Jun 5 | — | — |
| Lettuce | Mar 20 – Apr 3 | Apr 24 – May 8 | Apr 17 – May 22 | Jul 24 – Aug 21 |
| Kale | Mar 20 – Apr 3 | Apr 17 – May 1 | Apr 17 – May 1 | Jul 10 – Jul 31 |
| Broccoli | Mar 20 – Apr 3 | May 1 – May 15 | — | Jun 12 – Jul 3 |
| Cabbage | Mar 20 – Apr 3 | Apr 24 – May 8 | — | Jun 12 – Jul 3 |
| Cauliflower | Mar 20 – Apr 3 | May 1 – May 15 | — | Jun 12 – Jul 3 |
| Okra | Apr 3 – Apr 17 | Jun 5 – Jun 19 | Jun 5 – Jun 19 | — |
| Basil | Apr 3 – Apr 17 | May 22 – Jun 5 | — | — |
| Peas | — | — | Apr 3 – Apr 24 | Jun 26 – Jul 17 |
| Spinach | — | — | Apr 3 – Apr 24 | Jul 24 – Aug 14 |
| Radishes | — | — | Apr 10 – May 22 | Aug 7 – Aug 28 |
| Cucumbers | Apr 17 – Apr 24 | May 29 – Jun 5 | May 22 – Jun 5 | Jul 3 – Jul 17 |
| Zucchini & Summer Squash | Apr 17 – Apr 24 | — | May 22 – Jun 5 | Jul 10 – Jul 24 |
| Winter Squash & Pumpkins | Apr 17 – Apr 24 | — | May 22 – Jun 5 | — |
| Melons & Watermelon | Apr 17 – Apr 24 | May 29 – Jun 12 | — | — |
| Carrots | — | — | Apr 24 – May 22 | Jun 26 – Jul 10 |
| Beets | — | — | Apr 24 – May 22 | Jul 10 – Jul 24 |
| Potatoes | — | — | Apr 24 – May 15 | — |
| Swiss Chard | — | — | May 1 – May 29 | Jul 10 – Jul 24 |
| Cilantro | — | — | May 1 – May 22 | Jul 24 – Aug 14 |
| Green Beans | — | — | May 22 – Jun 12 | Jul 3 – Jul 17 |
| Sweet Corn | — | — | May 22 – Jun 5 | — |
| Sweet Potatoes | — | May 29 – Jun 19 | — | — |
| Garlic | — | — | — | Sep 4 – Oct 9 |
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 Willow West, AK weather station, 17 km away (elevation 207 ft (63 m)).
Frost dates near Willow
- Houston May 29 · Sep 7
- Talkeetna May 16 · Sep 16
- Big Lake May 29 · Sep 7
- Wasilla May 16 · Sep 23
- Trapper Creek May 16 · Sep 16
- Palmer May 22 · Sep 16
- Chugiak May 18 · Sep 20
- Sutton Jun 1 · Sep 6
- Eagle River May 9 · Sep 26
- Skwentna May 23 · Sep 9
Frequently asked questions
When is the last frost in Willow, AK?
The median last spring frost in Willow, AK is May 15. There is still about a 10% chance of frost after May 28, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Willow, AK?
The median first fall frost is September 18, with about a 10% chance of frost before September 4.
How long is the growing season in Willow, AK?
About 126 days between the median last spring frost and first fall frost.
What planting zone is Willow, AK?
Willow, AK is in USDA hardiness zone 3b.