Frost dates for 99703Fort Wainwright, AK
The average last spring frost in Fort Wainwright is May 16 and the average first fall frost is September 6, giving a typical growing season of about 112 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 16
- Average first fall frost
- Sep 6
- Growing season
- 112 days
Safer after May 29 (1-in-10 risk)
Possible by Aug 25 (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 14 · May 27 · Jun 8 | Aug 13 · Aug 27 · Sep 8 | 91 days | 100% |
| Frost / freeze (32°F) | May 5 · May 16 · May 29 | Aug 25 · Sep 6 · Sep 20 | 112 days | 100% |
| Hard freeze (28°F) | Apr 26 · May 7 · May 19 | Sep 4 · Sep 18 · Sep 30 | 133 days | 100% |
Planting calendar for Fort Wainwright
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 – May 17 |
| 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 – May 27 |
| Summer squash | Sow outdoors | Jun 1 – Jul 16 |
| Winter squash & pumpkins | Sow outdoors | Jun 15 – Jul 16 |
| Snap beans | Sow outdoors | Jun 1 – Jun 19 |
| Sweet corn | Sow outdoors | Jun 1 – May 17 |
| 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 7 – May 17 |
| Broccoli | Transplant outdoors (fall) | Jun 6 – Jun 17 |
| Cabbage | Start seeds indoors (spring) | Mar 18 – Apr 15 |
| Cabbage | Transplant outdoors (spring) | Apr 15 – May 16 |
| Cabbage | Start seeds indoors (fall) | Apr 27 – May 27 |
| Cabbage | Transplant outdoors (fall) | May 27 – Jun 27 |
| Leaf lettuce | Sow outdoors (spring) | Apr 15 – Jul 1 |
| Leaf lettuce | Sow outdoors (fall) | May 27 – Jul 13 |
| Spinach | Sow outdoors (spring) | Apr 8 – May 22 |
| Spinach | Sow outdoors (fall) | Jun 13 – Jul 18 |
| Radishes | Sow outdoors (spring) | Apr 15 – Jun 5 |
| Radishes | Sow outdoors (fall) | May 27 – Jul 28 |
| Kale | Sow outdoors (spring) | May 2 – May 22 |
| Kale | Sow outdoors (fall) | May 20 – Jun 27 |
| Carrots | Sow outdoors (spring) | May 16 – Jul 1 |
| Carrots | Sow outdoors (fall) | Apr 27 – Jun 12 |
| Garlic | Plant outdoors (fall) | Aug 27 – Sep 27 |
Where these dates come from
ZIP code 99703 is matched to the NOAA station Aurora, AK, 4.3 km away, at 443 ft elevation (7 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Aurora, AK (used) | 443 ft | May 16 | Sep 6 |
| Fairbanks Midtown, AK | 440 ft | May 13 | Sep 10 |
| College Obsy, AK | 597 ft | May 18 | Sep 6 |
| University Exp Stn, AK | 475 ft | May 16 | Sep 8 |
Frost dates near Fort Wainwright
- Fairbanks, AK 99701 · last May 16, first Sep 6
- North Pole, AK 99705 · last May 18, first Sep 5
- Ester, AK 99725 · last May 15, first Sep 16
- Eielson Afb, AK 99702 · last May 20, first Sep 1
- Two Rivers, AK 99716 · last May 30, first Sep 2
- Salcha, AK 99714 · last May 20, first Sep 1
- Fort Greely, AK 99731 · last May 17, first Sep 7
Frequently asked questions
- When is the last frost in Fort Wainwright, AK?
- For ZIP code 99703, the average last spring frost (32°F) is May 16, based on NOAA 1991-2020 climate normals for the Aurora, AK weather station. There is a 1-in-10 chance of a frost after May 29.
- When is the first frost in Fort Wainwright, AK?
- The average first fall frost (32°F) is September 6. There is a 1-in-10 chance of frost by August 25, so tender plants are at risk from that point on.
- How long is the growing season in 99703?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 112 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.