Last spring frost
May 6
Frost Dates for Gustavus, AK
First fall frost
Oct 10
Growing season
154 days
In an average year around Gustavus, AK, the last spring frost (32°F) is about May 6 and the first fall frost is about Oct 10, giving roughly a 154-day growing season. To be safe most years, wait until Apr 22 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Jun 10 | May 24 | May 8 |
| Freeze (32°F) | May 26 | May 6 | Apr 22 |
| Hard (28°F) | May 10 | Apr 20 | Apr 1 |
| Severe (24°F) | Apr 29 | Apr 3 | Mar 12 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 10 | Jun 3 | May 31 | May 27 | May 24 | May 20 | May 17 | May 13 | May 8 |
| 32°F | May 26 | May 18 | May 13 | May 10 | May 6 | May 3 | Apr 30 | Apr 27 | Apr 22 |
| 28°F | May 10 | May 3 | Apr 29 | Apr 24 | Apr 20 | Apr 16 | Apr 11 | Apr 6 | Apr 1 |
| 24°F | Apr 29 | Apr 19 | Apr 12 | Apr 7 | Apr 3 | Mar 31 | Mar 27 | Mar 21 | Mar 12 |
| 20°F | Apr 9 | Apr 1 | Mar 28 | Mar 23 | Mar 19 | Mar 15 | Mar 10 | Mar 5 | Feb 24 |
| 16°F | Mar 29 | Mar 22 | Mar 17 | Mar 11 | Mar 7 | Mar 2 | Feb 24 | Feb 13 | Jan 31 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Sep 5 | Sep 26 | Oct 11 |
| Freeze (32°F) | Sep 19 | Oct 10 | Oct 28 |
| Hard (28°F) | Sep 28 | Oct 28 | Nov 17 |
| Severe (24°F) | Oct 21 | Nov 13 | Dec 3 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 5 | Sep 12 | Sep 19 | Sep 22 | Sep 26 | Sep 29 | Oct 1 | Oct 5 | Oct 11 |
| 32°F | Sep 19 | Sep 27 | Oct 1 | Oct 6 | Oct 10 | Oct 14 | Oct 19 | Oct 23 | Oct 28 |
| 28°F | Sep 28 | Oct 9 | Oct 18 | Oct 24 | Oct 28 | Nov 1 | Nov 4 | Nov 9 | Nov 17 |
| 24°F | Oct 21 | Oct 31 | Nov 5 | Nov 9 | Nov 13 | Nov 18 | Nov 21 | Nov 26 | Dec 3 |
| 20°F | Nov 5 | Nov 13 | Nov 18 | Nov 22 | Nov 27 | Dec 1 | Dec 8 | Dec 16 | Dec 27 |
| 16°F | Nov 16 | Nov 25 | Dec 1 | Dec 6 | Dec 12 | Dec 22 | Dec 29 | Jan 5 | Jan 21 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Glacier Bay, Ak, about 28 miles away@if(!empty($station['elevation_ft'])), at 45 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Gustavus, AK?
On average, the last spring frost (32°F) around Gustavus, AK is about May 6. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 22.
When is the first frost in the fall?
The first fall frost around Gustavus, AK typically arrives about Oct 10. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around May 6 on average, or Apr 22 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 154 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 99827 Planting calendar → Alaska frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026