Frost dates for 99836Port Alexander, AK
The average last spring frost in Port Alexander is April 18 and the average first fall frost is November 5, giving a typical growing season of about 198 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 18
- Average first fall frost
- Nov 5
- Growing season
- 198 days
Safer after May 5 (1-in-10 risk)
Possible by Oct 16 (1-in-10 risk)
First frost typically in 9 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 25 · May 10 · May 25 | Sep 29 · Oct 14 · Nov 1 | 155 days | 100% |
| Frost / freeze (32°F) | Mar 31 · Apr 18 · May 5 | Oct 16 · Nov 5 · Nov 25 | 198 days | 100% |
| Hard freeze (28°F) | Mar 4 · Mar 26 · Apr 11 | Nov 4 · Nov 24 · Dec 26 | 243 days | 100% |
Planting calendar for Port Alexander
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 18 – May 24 |
| Tomatoes | Transplant outdoors | May 4 – Jul 16 |
| Peppers | Start seeds indoors | Mar 18 – Apr 18 |
| Peppers | Transplant outdoors | May 18 – Jun 18 |
| Eggplant | Start seeds indoors | Apr 4 – May 3 |
| Eggplant | Transplant outdoors | May 18 – Jun 18 |
| Cucumbers | Sow outdoors | May 18 – Jul 26 |
| Summer squash | Sow outdoors | May 4 – Jun 18 |
| Winter squash & pumpkins | Sow outdoors | May 18 – Jun 18 |
| Snap beans | Sow outdoors | May 4 – Aug 18 |
| Sweet corn | Sow outdoors | May 4 – Jul 16 |
| Watermelon & cantaloupe | Sow outdoors | May 18 – Jun 18 |
| Okra | Sow outdoors | May 11 – Jun 3 |
| Peas | Sow outdoors (spring) | Mar 18 – May 3 |
| Potatoes | Plant outdoors (spring) | Mar 18 – May 18 |
| Onions | Start seeds indoors (spring) | Feb 4 – Mar 3 |
| Onions | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (spring) | Feb 28 – Apr 3 |
| Broccoli | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (fall) | Jul 6 – Jul 16 |
| Broccoli | Transplant outdoors (fall) | Aug 5 – Aug 16 |
| Cabbage | Start seeds indoors (spring) | Feb 18 – Mar 18 |
| Cabbage | Transplant outdoors (spring) | Mar 18 – Apr 18 |
| Cabbage | Start seeds indoors (fall) | Jun 26 – Jul 26 |
| Cabbage | Transplant outdoors (fall) | Jul 26 – Aug 26 |
| Leaf lettuce | Sow outdoors (spring) | Mar 18 – Jun 3 |
| Leaf lettuce | Sow outdoors (fall) | Jul 26 – Sep 11 |
| Spinach | Sow outdoors (spring) | Mar 11 – Apr 24 |
| Spinach | Sow outdoors (fall) | Aug 12 – Sep 16 |
| Radishes | Sow outdoors (spring) | Mar 18 – May 8 |
| Radishes | Sow outdoors (fall) | Jul 26 – Sep 26 |
| Kale | Sow outdoors (spring) | Apr 4 – Apr 24 |
| Kale | Sow outdoors (fall) | Jul 19 – Aug 26 |
| Carrots | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Carrots | Sow outdoors (fall) | Jun 26 – Aug 11 |
| Garlic | Plant outdoors (fall) | Oct 26 – Nov 26 |
Where these dates come from
ZIP code 99836 is matched to the NOAA station Port Alexander, AK, 0.3 km away, at 12 ft elevation (40 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Port Alexander, AK (used) | 12 ft | Apr 18 | Nov 5 |
| Little Port Walter, AK | 14 ft | Apr 21 | Oct 31 |
| Pt Baker, AK | 20 ft | Apr 19 | Oct 25 |
| Sitka 1 Ne, AK | 78 ft | May 3 | Oct 18 |
Frost dates near Port Alexander
- Point Baker, AK 99927 · last Apr 19, first Oct 25
- Kake, AK 99830 · last Apr 29, first Oct 17
- Sitka, AK 99835 · last May 3, first Oct 18
Frequently asked questions
- When is the last frost in Port Alexander, AK?
- For ZIP code 99836, the average last spring frost (32°F) is April 18, based on NOAA 1991-2020 climate normals for the Port Alexander, AK weather station. There is a 1-in-10 chance of a frost after May 5.
- When is the first frost in Port Alexander, AK?
- The average first fall frost (32°F) is November 5. There is a 1-in-10 chance of frost by October 16, so tender plants are at risk from that point on.
- How long is the growing season in 99836?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 198 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.