Last frost date in Anchorage, AK
In Anchorage, the last spring frost comes around May 16 in an average year. Wait until June 9 if you want 90% odds of no more frost. The first fall frost usually arrives about September 20, which leaves 125 frost-free days. An early freeze before September 4 happens one year in ten.
- Safe after (10% risk)
- Jun 9
- Average first frost
- Sep 20
- Frost-free season
- 125 days
- Hard freeze (28°F) ends
- May 1
Hard freeze likely Thu night, low 18°F
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2218°hard freeze
- FriOct 2328°hard freeze
- SatOct 2431°frost
- SunOct 2530°frost
- MonOct 2631°frost
- TueOct 2731°frost
Planting calendar for Anchorage
Windows count forward or back from the average frost dates above. Click a crop for dates across Alaska.
TomatoesMay 23–Jun 6
PumpkinsMay 30–Jun 13
SunflowersMay 16–Jun 6
CucumbersMay 30–Jun 6
CornMay 23–Jun 6
Sweet potatoesJun 6–Jun 20
WatermelonMay 30–Jun 13
Green beansMay 23–Jun 13
ZucchiniMay 23–Jun 6
OkraJun 6–Jun 20
PeppersMay 30–Jun 13
BasilMay 23–Jun 6
Butternut squashMay 23–Jun 6
CantaloupeMay 30–Jun 13
EggplantMay 30–Jun 13
PotatoesApr 18–May 2
OnionsApr 4–Apr 25
CarrotsApr 25–May 30
LettuceMay 2–May 23
BroccoliApr 18–May 2
BeetsApr 18–May 30
PeasApr 4–Apr 18
CabbageApr 18–May 2
RadishesApr 11–May 23
Brussels sproutsMay 2–May 16
SpinachApr 4–Apr 25
CilantroMay 2–May 23
KaleApr 18–May 2
Collard greensApr 18–May 2
TurnipsApr 18–May 2
DillMay 16–May 30
CeleryMay 23–May 30
CauliflowerMay 2–May 16
LeeksMay 2–May 16
Swiss chardMay 2–May 30
ParsleyMay 2–May 23
Tulip bulbsSep 6–Oct 11
GarlicAug 30–Oct 4
Daffodil bulbsAug 23–Oct 4
StrawberriesApr 18–May 2
AsparagusApr 18–May 2The frost-free season here is short for pumpkins, sweet potatoes. Start them indoors and look for early varieties.
Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | May 2 | May 16 | Jun 9 | Sep 4 | Sep 20 | Oct 3 |
| Hard freeze, 28°F | Apr 16 | May 1 | May 15 | Sep 18 | Oct 1 | Oct 16 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station Eagle River Nature Center (USC00502642) sits 4.2 miles from the center of Anchorage at 520 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Anchorage, AK?
The average last frost date in Anchorage is May 16, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after June 9.
When is the first frost in Anchorage?
The first frost in fall usually comes around September 20. One year in ten it arrives before September 4.
How long is the growing season in Anchorage?
About 125 days between the average last and first frost.
When should I plant tomatoes in Anchorage?
Plant tomato seedlings outside from May 23 to June 6. Start seeds indoors six to eight weeks earlier.