Frost dates for 99693Whittier, AK
The average last spring frost in Whittier is April 25 and the average first fall frost is October 14, giving a typical growing season of about 172 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 25
- Average first fall frost
- Oct 14
- Growing season
- 172 days
Safer after May 8 (1-in-10 risk)
Possible by Oct 1 (1-in-10 risk)
Last frost typically in 180 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 30 · May 11 · May 23 | Sep 19 · Oct 1 · Oct 16 | 143 days | 100% |
| Frost / freeze (32°F) | Apr 12 · Apr 25 · May 8 | Oct 1 · Oct 14 · Oct 30 | 172 days | 100% |
| Hard freeze (28°F) | Mar 30 · Apr 11 · Apr 25 | Oct 10 · Oct 26 · Nov 11 | 198 days | 100% |
Planting calendar for Whittier
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 25 – May 31 |
| Tomatoes | Transplant outdoors | May 11 – Jun 24 |
| Peppers | Start seeds indoors | Mar 25 – Apr 25 |
| Peppers | Transplant outdoors | May 25 – Jun 25 |
| Eggplant | Start seeds indoors | Apr 11 – May 10 |
| Eggplant | Transplant outdoors | May 25 – Jun 25 |
| Cucumbers | Sow outdoors | May 25 – Jul 4 |
| Summer squash | Sow outdoors | May 11 – Jun 25 |
| Winter squash & pumpkins | Sow outdoors | May 25 – Jun 25 |
| Snap beans | Sow outdoors | May 11 – Jul 27 |
| Sweet corn | Sow outdoors | May 11 – Jun 24 |
| Watermelon & cantaloupe | Sow outdoors | May 25 – Jun 25 |
| Okra | Sow outdoors | May 18 – Jun 10 |
| Peas | Sow outdoors (spring) | Mar 25 – May 10 |
| Potatoes | Plant outdoors (spring) | Mar 25 – May 25 |
| Onions | Start seeds indoors (spring) | Feb 11 – Mar 10 |
| Onions | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (spring) | Mar 7 – Apr 10 |
| Broccoli | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (fall) | Jun 14 – Jun 24 |
| Broccoli | Transplant outdoors (fall) | Jul 14 – Jul 25 |
| Cabbage | Start seeds indoors (spring) | Feb 25 – Mar 25 |
| Cabbage | Transplant outdoors (spring) | Mar 25 – Apr 25 |
| Cabbage | Start seeds indoors (fall) | Jun 4 – Jul 4 |
| Cabbage | Transplant outdoors (fall) | Jul 4 – Aug 4 |
| Leaf lettuce | Sow outdoors (spring) | Mar 25 – Jun 10 |
| Leaf lettuce | Sow outdoors (fall) | Jul 4 – Aug 20 |
| Spinach | Sow outdoors (spring) | Mar 18 – May 1 |
| Spinach | Sow outdoors (fall) | Jul 21 – Aug 25 |
| Radishes | Sow outdoors (spring) | Mar 25 – May 15 |
| Radishes | Sow outdoors (fall) | Jul 4 – Sep 4 |
| Kale | Sow outdoors (spring) | Apr 11 – May 1 |
| Kale | Sow outdoors (fall) | Jun 27 – Aug 4 |
| Carrots | Sow outdoors (spring) | Apr 25 – Jun 10 |
| Carrots | Sow outdoors (fall) | Jun 4 – Jul 20 |
| Garlic | Plant outdoors (fall) | Oct 4 – Nov 4 |
Where these dates come from
ZIP code 99693 is matched to the NOAA station Whittier, AK, 0.3 km away, at 60 ft elevation (34 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Whittier, AK (used) | 60 ft | Apr 25 | Oct 14 |
| Portage Glacier V C, AK | 103 ft | May 27 | Sep 12 |
| Alyeska, AK | 272 ft | May 8 | Sep 29 |
| Wally Noerenberg Hatchery, AK | 35 ft | May 20 | Oct 9 |
Frost dates near Whittier
- Girdwood, AK 99587 · last May 8, first Sep 29
- Moose Pass, AK 99631 · last May 31, first Sep 8
- Hope, AK 99605 · last May 18, first Sep 23
- Anchorage, AK 99519 · last May 18, first Sep 23
- Indian, AK 99540 · last May 18, first Sep 23
- Cooper Landing, AK 99572 · last Jun 12, first Sep 1
- Eagle River, AK 99577 · last May 9, first Sep 26
- Seward, AK 99664 · last May 2, first Oct 7
Frequently asked questions
- When is the last frost in Whittier, AK?
- For ZIP code 99693, the average last spring frost (32°F) is April 25, based on NOAA 1991-2020 climate normals for the Whittier, AK weather station. There is a 1-in-10 chance of a frost after May 8.
- When is the first frost in Whittier, AK?
- The average first fall frost (32°F) is October 14. There is a 1-in-10 chance of frost by October 1, so tender plants are at risk from that point on.
- How long is the growing season in 99693?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 172 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.