Last spring frost
Jun 4
Frost Dates for St. Paul, AK
First fall frost
Sep 28
Growing season
114 days
In an average year around St. Paul, AK, the last spring frost (32°F) is about Jun 4 and the first fall frost is about Sep 28, giving roughly a 114-day growing season. To be safe most years, wait until May 16 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%) |
|---|---|---|---|
| Freeze (32°F) | Jun 25 | Jun 4 | May 16 |
| Hard (28°F) | Jun 6 | May 17 | May 1 |
| Severe (24°F) | May 17 | May 2 | Apr 14 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 32°F | Jun 25 | Jun 18 | Jun 12 | Jun 8 | Jun 4 | Jun 1 | May 29 | May 24 | May 16 |
| 28°F | Jun 6 | May 30 | May 25 | May 21 | May 17 | May 13 | May 10 | May 5 | May 1 |
| 24°F | May 17 | May 12 | May 8 | May 5 | May 2 | Apr 30 | Apr 26 | Apr 21 | Apr 14 |
| 20°F | May 5 | May 1 | Apr 26 | Apr 23 | Apr 20 | Apr 15 | Apr 11 | Apr 7 | Apr 2 |
| 16°F | Apr 24 | Apr 19 | Apr 15 | Apr 11 | Apr 7 | Apr 4 | Apr 2 | Mar 30 | Mar 21 |
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%) |
|---|---|---|---|
| Freeze (32°F) | Sep 11 | Sep 28 | Oct 15 |
| Hard (28°F) | Sep 26 | Oct 15 | Nov 4 |
| Severe (24°F) | Oct 10 | Nov 4 | Nov 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 32°F | Sep 11 | Sep 16 | Sep 20 | Sep 25 | Sep 28 | Oct 1 | Oct 5 | Oct 8 | Oct 15 |
| 28°F | Sep 26 | Oct 3 | Oct 7 | Oct 11 | Oct 15 | Oct 19 | Oct 23 | Oct 29 | Nov 4 |
| 24°F | Oct 10 | Oct 20 | Oct 26 | Nov 1 | Nov 4 | Nov 10 | Nov 15 | Nov 19 | Nov 25 |
| 20°F | Nov 3 | Nov 9 | Nov 15 | Nov 20 | Nov 23 | Nov 26 | Nov 29 | Dec 3 | Dec 10 |
| 16°F | Nov 15 | Nov 22 | Nov 26 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 19 | Dec 24 |
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: St Paul Island Ap, Ak, about 4.1 miles away@if(!empty($station['elevation_ft'])), at 35 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 St. Paul, AK?
On average, the last spring frost (32°F) around St. Paul, AK is about Jun 4. In cooler years it can run later, so for a safer bet many gardeners wait until May 16.
When is the first frost in the fall?
The first fall frost around St. Paul, AK typically arrives about Sep 28. 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 Jun 4 on average, or May 16 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 114 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 99660 Planting calendar → Alaska frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026