Frost dates for 99623Wasilla, AK
The average last spring frost in Wasilla is May 16 and the average first fall frost is September 23, giving a typical growing season of about 128 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 16
- Average first fall frost
- Sep 23
- Growing season
- 128 days
Safer after May 31 (1-in-10 risk)
Possible by Sep 8 (1-in-10 risk)
Last frost typically in 201 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) | May 19 · Jun 1 · Jun 10 | Aug 28 · Sep 10 · Sep 23 | 100 days | 100% |
| Frost / freeze (32°F) | May 1 · May 16 · May 31 | Sep 8 · Sep 23 · Oct 5 | 128 days | 100% |
| Hard freeze (28°F) | Apr 15 · May 1 · May 16 | Sep 19 · Oct 3 · Oct 18 | 156 days | 100% |
Planting calendar for Wasilla
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 | Apr 15 – Jun 21 |
| Tomatoes | Transplant outdoors | Jun 1 – Jun 3 |
| Peppers | Start seeds indoors | Apr 15 – May 16 |
| Peppers | Transplant outdoors | Jun 15 – Jul 16 |
| Eggplant | Start seeds indoors | May 2 – May 31 |
| Eggplant | Transplant outdoors | Jun 15 – Jul 16 |
| Cucumbers | Sow outdoors | Jun 15 – Jun 13 |
| Summer squash | Sow outdoors | Jun 1 – Jul 16 |
| Winter squash & pumpkins | Sow outdoors | Jun 15 – Jul 16 |
| Snap beans | Sow outdoors | Jun 1 – Jul 6 |
| Sweet corn | Sow outdoors | Jun 1 – Jun 3 |
| Watermelon & cantaloupe | Sow outdoors | Jun 15 – Jul 16 |
| Okra | Sow outdoors | Jun 8 – Jul 1 |
| Peas | Sow outdoors (spring) | Apr 15 – May 31 |
| Potatoes | Plant outdoors (spring) | Apr 15 – Jun 15 |
| Onions | Start seeds indoors (spring) | Mar 4 – Mar 31 |
| Onions | Transplant outdoors (spring) | May 2 – May 31 |
| Broccoli | Start seeds indoors (spring) | Mar 28 – May 1 |
| Broccoli | Transplant outdoors (spring) | May 2 – May 31 |
| Broccoli | Start seeds indoors (fall) | May 24 – Jun 3 |
| Broccoli | Transplant outdoors (fall) | Jun 23 – Jul 4 |
| Cabbage | Start seeds indoors (spring) | Mar 18 – Apr 15 |
| Cabbage | Transplant outdoors (spring) | Apr 15 – May 16 |
| Cabbage | Start seeds indoors (fall) | May 14 – Jun 13 |
| Cabbage | Transplant outdoors (fall) | Jun 13 – Jul 14 |
| Leaf lettuce | Sow outdoors (spring) | Apr 15 – Jul 1 |
| Leaf lettuce | Sow outdoors (fall) | Jun 13 – Jul 30 |
| Spinach | Sow outdoors (spring) | Apr 8 – May 22 |
| Spinach | Sow outdoors (fall) | Jun 30 – Aug 4 |
| Radishes | Sow outdoors (spring) | Apr 15 – Jun 5 |
| Radishes | Sow outdoors (fall) | Jun 13 – Aug 14 |
| Kale | Sow outdoors (spring) | May 2 – May 22 |
| Kale | Sow outdoors (fall) | Jun 6 – Jul 14 |
| Carrots | Sow outdoors (spring) | May 16 – Jul 1 |
| Carrots | Sow outdoors (fall) | May 14 – Jun 29 |
| Garlic | Plant outdoors (fall) | Sep 13 – Oct 14 |
Where these dates come from
ZIP code 99623 is matched to the NOAA station Anderson Lake, AK, 15.8 km away, at 458 ft elevation (84 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Anderson Lake, AK (used) | 458 ft | May 16 | Sep 23 |
| Eklutna Wtp, AK | 640 ft | May 18 | Sep 20 |
| Matanuska Exp Farm, AK | 172 ft | May 14 | Sep 20 |
| Ben'S Farm, AK | 127 ft | May 12 | Sep 20 |
Frost dates near Wasilla
- Wasilla, AK 99687 · last May 14, first Sep 20
- Houston, AK 99694 · last May 29, first Sep 7
- Chugiak, AK 99567 · last May 21, first Sep 15
- Big Lake, AK 99652 · last May 29, first Sep 7
- Eagle River, AK 99577 · last May 9, first Sep 26
- Palmer, AK 99645 · last May 22, first Sep 16
- Anchorage, AK 99504 · last May 1, first Sep 29
- Willow, AK 99688 · last May 29, first Sep 7
Frequently asked questions
- When is the last frost in Wasilla, AK?
- For ZIP code 99623, the average last spring frost (32°F) is May 16, based on NOAA 1991-2020 climate normals for the Anderson Lake, AK weather station. There is a 1-in-10 chance of a frost after May 31.
- When is the first frost in Wasilla, AK?
- The average first fall frost (32°F) is September 23. There is a 1-in-10 chance of frost by September 8, so tender plants are at risk from that point on.
- How long is the growing season in 99623?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 128 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.