Frost dates for 99755Denali National Park, AK
The average last spring frost in Denali National Park is May 25 and the average first fall frost is September 8, giving a typical growing season of about 105 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 25
- Average first fall frost
- Sep 8
- Growing season
- 105 days
Safer after Jun 3 (1-in-10 risk)
Possible by Aug 26 (1-in-10 risk)
Last frost typically in 208 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 26 · Jun 4 · Jun 16 | Aug 14 · Aug 27 · Sep 9 | 82 days | 100% |
| Frost / freeze (32°F) | May 13 · May 25 · Jun 3 | Aug 26 · Sep 8 · Sep 20 | 105 days | 100% |
| Hard freeze (28°F) | May 3 · May 13 · May 24 | Sep 5 · Sep 19 · Sep 29 | 126 days | 100% |
Planting calendar for Denali National Park
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 24 – Jun 30 |
| Tomatoes | Transplant outdoors | Jun 10 – May 19 |
| Peppers | Start seeds indoors | Apr 24 – May 25 |
| Peppers | Transplant outdoors | Jun 24 – Jul 25 |
| Eggplant | Start seeds indoors | May 11 – Jun 9 |
| Eggplant | Transplant outdoors | Jun 24 – Jul 25 |
| Cucumbers | Sow outdoors | Jun 24 – May 29 |
| Summer squash | Sow outdoors | Jun 10 – Jul 25 |
| Winter squash & pumpkins | Sow outdoors | Jun 24 – Jul 25 |
| Snap beans | Sow outdoors | Jun 10 – Jun 21 |
| Sweet corn | Sow outdoors | Jun 10 – May 19 |
| Watermelon & cantaloupe | Sow outdoors | Jun 24 – Jul 25 |
| Okra | Sow outdoors | Jun 17 – Jul 10 |
| Peas | Sow outdoors (spring) | Apr 24 – Jun 9 |
| Potatoes | Plant outdoors (spring) | Apr 24 – Jun 24 |
| Onions | Start seeds indoors (spring) | Mar 13 – Apr 9 |
| Onions | Transplant outdoors (spring) | May 11 – Jun 9 |
| Broccoli | Start seeds indoors (spring) | Apr 6 – May 10 |
| Broccoli | Transplant outdoors (spring) | May 11 – Jun 9 |
| Broccoli | Start seeds indoors (fall) | May 9 – May 19 |
| Broccoli | Transplant outdoors (fall) | Jun 8 – Jun 19 |
| Cabbage | Start seeds indoors (spring) | Mar 27 – Apr 24 |
| Cabbage | Transplant outdoors (spring) | Apr 24 – May 25 |
| Cabbage | Start seeds indoors (fall) | Apr 29 – May 29 |
| Cabbage | Transplant outdoors (fall) | May 29 – Jun 29 |
| Leaf lettuce | Sow outdoors (spring) | Apr 24 – Jul 10 |
| Leaf lettuce | Sow outdoors (fall) | May 29 – Jul 15 |
| Spinach | Sow outdoors (spring) | Apr 17 – May 31 |
| Spinach | Sow outdoors (fall) | Jun 15 – Jul 20 |
| Radishes | Sow outdoors (spring) | Apr 24 – Jun 14 |
| Radishes | Sow outdoors (fall) | May 29 – Jul 30 |
| Kale | Sow outdoors (spring) | May 11 – May 31 |
| Kale | Sow outdoors (fall) | May 22 – Jun 29 |
| Carrots | Sow outdoors (spring) | May 25 – Jul 10 |
| Carrots | Sow outdoors (fall) | Apr 29 – Jun 14 |
| Garlic | Plant outdoors (fall) | Aug 29 – Sep 29 |
Where these dates come from
ZIP code 99755 is matched to the NOAA station Denali 27 N, AK, 45.2 km away, at 2,225 ft elevation (1,787 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Denali 27 N, AK (used) | 2,225 ft | May 25 | Sep 8 |
| Mckinley Park, AK | 2,070 ft | Jun 6 | Aug 25 |
| Cantwell 2 E, AK | 2,132 ft | — | — |
| Healy, AK | 1,417 ft | May 27 | Sep 1 |
Frost dates near Denali National Park
- Cantwell, AK 99729 · last —, first —
- Healy, AK 99743 · last May 27, first Sep 1
- Clear, AK 99704 · last May 24, first Sep 4
- Anderson, AK 99744 · last May 15, first Sep 11
Frequently asked questions
- When is the last frost in Denali National Park, AK?
- For ZIP code 99755, the average last spring frost (32°F) is May 25, based on NOAA 1991-2020 climate normals for the Denali 27 N, AK weather station. There is a 1-in-10 chance of a frost after June 3.
- When is the first frost in Denali National Park, AK?
- The average first fall frost (32°F) is September 8. There is a 1-in-10 chance of frost by August 26, so tender plants are at risk from that point on.
- How long is the growing season in 99755?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 105 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.