Frost Dates for Anchorage, AK
In Anchorage, AK, the average last spring frost is around May 16 and the average first fall frost around Sep 20, for a growing season of about 125 days. For frost-tender plants, wait until Jun 9, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Eagle Rvr Nature Ctr, AK weather station, 4 miles away, elevation 520 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.
Frost probability by date
Chance of a 32°F frost after the spring date, or before the fall date.
| Chance | Last spring frost | First fall frost |
|---|---|---|
| 10% | Jun 9 | Sep 4 |
| 20% | May 29 | Sep 10 |
| 30% | May 23 | Sep 14 |
| 40% | May 19 | Sep 17 |
| 50% | May 16 | Sep 20 |
| 60% | May 13 | Sep 22 |
| 70% | May 10 | Sep 25 |
| 80% | May 7 | Sep 28 |
| 90% | May 2 | Oct 3 |
Light frost vs. hard freeze
Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.
| Temperature | Last in spring | First in fall |
|---|---|---|
| Light frost (36°F) | May 31 | Sep 6 |
| Frost / freeze (32°F) | May 16 | Sep 20 |
| Hard freeze (28°F) | May 1 | Oct 1 |
Planting calendar for Anchorage
Transplant May 23 – Jun 6
Transplant May 30 – Jun 13
Transplant May 30 – Jun 13
Transplant May 23 – Jun 6
Sow or transplant May 23 – Jun 6
Sow or transplant May 23 – Jun 6
Sow or transplant May 30 – Jun 13
Sow or transplant Apr 18 – May 2
Fall sowing Jul 26 – Aug 23
Fall sowing Jul 26 – Aug 16
Fall sowing Jul 12 – Jul 26
Sow or transplant Apr 18 – May 2
Fall sowing Jul 12 – Aug 9
Transplant May 2 – May 16
Fall sowing Jun 28 – Jul 12
Transplant Apr 25 – May 9
Fall sowing Jun 28 – Jul 12
Fall sowing Jun 28 – Jul 12
Fall sowing Aug 9 – Aug 30
Fall sowing Jul 12 – Jul 26
Plant Apr 18 – May 2
Based on the average last frost (May 16) and first frost (Sep 20). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.