Frost dates for 99950Ketchikan, AK
The average last spring frost in Ketchikan is April 4 and the average first fall frost is November 9, giving a typical growing season of about 218 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 4
- Average first fall frost
- Nov 9
- Growing season
- 218 days
Safer after Apr 25 (1-in-10 risk)
Possible by Oct 19 (1-in-10 risk)
First frost typically in 8 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 8 · Apr 27 · May 14 | Oct 5 · Oct 22 · Nov 8 | 178 days | 100% |
| Frost / freeze (32°F) | Mar 15 · Apr 4 · Apr 25 | Oct 19 · Nov 9 · Dec 2 | 218 days | 100% |
| Hard freeze (28°F) | Feb 15 · Mar 13 · Apr 5 | Nov 4 · Nov 26 · Dec 22 | 259 days | 100% |
Planting calendar for Ketchikan
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 4 – May 10 |
| Tomatoes | Transplant outdoors | Apr 20 – Jul 20 |
| Peppers | Start seeds indoors | Mar 4 – Apr 4 |
| Peppers | Transplant outdoors | May 4 – Jun 4 |
| Eggplant | Start seeds indoors | Mar 21 – Apr 19 |
| Eggplant | Transplant outdoors | May 4 – Jun 4 |
| Cucumbers | Sow outdoors | May 4 – Jul 30 |
| Summer squash | Sow outdoors | Apr 20 – Jun 4 |
| Winter squash & pumpkins | Sow outdoors | May 4 – Jun 4 |
| Snap beans | Sow outdoors | Apr 20 – Aug 22 |
| Sweet corn | Sow outdoors | Apr 20 – Jul 20 |
| Watermelon & cantaloupe | Sow outdoors | May 4 – Jun 4 |
| Okra | Sow outdoors | Apr 27 – May 20 |
| Peas | Sow outdoors (spring) | Mar 4 – Apr 19 |
| Potatoes | Plant outdoors (spring) | Mar 4 – May 4 |
| Onions | Start seeds indoors (spring) | Jan 21 – Feb 17 |
| Onions | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (spring) | Feb 14 – Mar 20 |
| Broccoli | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (fall) | Jul 10 – Jul 20 |
| Broccoli | Transplant outdoors (fall) | Aug 9 – Aug 20 |
| Cabbage | Start seeds indoors (spring) | Feb 4 – Mar 4 |
| Cabbage | Transplant outdoors (spring) | Mar 4 – Apr 4 |
| Cabbage | Start seeds indoors (fall) | Jun 30 – Jul 30 |
| Cabbage | Transplant outdoors (fall) | Jul 30 – Aug 30 |
| Leaf lettuce | Sow outdoors (spring) | Mar 4 – May 20 |
| Leaf lettuce | Sow outdoors (fall) | Jul 30 – Sep 15 |
| Spinach | Sow outdoors (spring) | Feb 25 – Apr 10 |
| Spinach | Sow outdoors (fall) | Aug 16 – Sep 20 |
| Radishes | Sow outdoors (spring) | Mar 4 – Apr 24 |
| Radishes | Sow outdoors (fall) | Jul 30 – Sep 30 |
| Kale | Sow outdoors (spring) | Mar 21 – Apr 10 |
| Kale | Sow outdoors (fall) | Jul 23 – Aug 30 |
| Carrots | Sow outdoors (spring) | Apr 4 – May 20 |
| Carrots | Sow outdoors (fall) | Jun 30 – Aug 15 |
| Garlic | Plant outdoors (fall) | Oct 30 – Nov 30 |
Where these dates come from
ZIP code 99950 is matched to the NOAA station Beaver Falls, AK, 3.5 km away, at 35 ft elevation (11 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Beaver Falls, AK (used) | 35 ft | Apr 4 | Nov 9 |
| Ketchikan Intl Ap, AK | 76 ft | Apr 22 | Oct 23 |
| Ketchikan 10N, AK | 295 ft | Apr 20 | Oct 26 |
| Metlakatla 6 S, AK | 105 ft | Apr 14 | Oct 25 |
Frost dates near Ketchikan
- Ketchikan, AK 99901 · last Apr 22, first Oct 23
- Ward Cove, AK 99928 · last Apr 22, first Oct 23
- Metlakatla, AK 99926 · last Apr 4, first Oct 31
- Meyers Chuck, AK 99903 · last May 1, first Oct 13
- Thorne Bay, AK 99919 · last May 1, first Oct 13
- Hydaburg, AK 99922 · last Apr 14, first Nov 1
- Coffman Cove, AK 99918 · last Apr 29, first Oct 16
Frequently asked questions
- When is the last frost in Ketchikan, AK?
- For ZIP code 99950, the average last spring frost (32°F) is April 4, based on NOAA 1991-2020 climate normals for the Beaver Falls, AK weather station. There is a 1-in-10 chance of a frost after April 25.
- When is the first frost in Ketchikan, AK?
- The average first fall frost (32°F) is November 9. There is a 1-in-10 chance of frost by October 19, so tender plants are at risk from that point on.
- How long is the growing season in 99950?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 218 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.