Frost dates for 86515Window Rock, AZ
The average last spring frost in Window Rock is May 29 and the average first fall frost is September 28, giving a typical growing season of about 121 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 29
- Average first fall frost
- Sep 28
- Growing season
- 121 days
Safer after Jun 10 (1-in-10 risk)
Possible by Sep 16 (1-in-10 risk)
Last frost typically in 207 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 28 · Jun 8 · Jun 19 | Sep 9 · Sep 20 · Oct 1 | 102 days | 100% |
| Frost / freeze (32°F) | May 12 · May 29 · Jun 10 | Sep 16 · Sep 28 · Oct 8 | 121 days | 100% |
| Hard freeze (28°F) | Apr 30 · May 13 · Jun 1 | Sep 23 · Oct 4 · Oct 20 | 143 days | 100% |
Planting calendar for Window Rock
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 28 – Jul 4 |
| Tomatoes | Transplant outdoors | Jun 14 – Jun 8 |
| Peppers | Start seeds indoors | Apr 28 – May 29 |
| Peppers | Transplant outdoors | Jun 28 – Jul 29 |
| Eggplant | Start seeds indoors | May 15 – Jun 13 |
| Eggplant | Transplant outdoors | Jun 28 – Jul 29 |
| Cucumbers | Sow outdoors | Jun 28 – Jun 18 |
| Summer squash | Sow outdoors | Jun 14 – Jul 29 |
| Winter squash & pumpkins | Sow outdoors | Jun 28 – Jul 29 |
| Snap beans | Sow outdoors | Jun 14 – Jul 11 |
| Sweet corn | Sow outdoors | Jun 14 – Jun 8 |
| Watermelon & cantaloupe | Sow outdoors | Jun 28 – Jul 29 |
| Okra | Sow outdoors | Jun 21 – Jul 14 |
| Peas | Sow outdoors (spring) | Apr 28 – Jun 13 |
| Potatoes | Plant outdoors (spring) | Apr 28 – Jun 28 |
| Onions | Start seeds indoors (spring) | Mar 17 – Apr 13 |
| Onions | Transplant outdoors (spring) | May 15 – Jun 13 |
| Broccoli | Start seeds indoors (spring) | Apr 10 – May 14 |
| Broccoli | Transplant outdoors (spring) | May 15 – Jun 13 |
| Broccoli | Start seeds indoors (fall) | May 29 – Jun 8 |
| Broccoli | Transplant outdoors (fall) | Jun 28 – Jul 9 |
| Cabbage | Start seeds indoors (spring) | Mar 31 – Apr 28 |
| Cabbage | Transplant outdoors (spring) | Apr 28 – May 29 |
| Cabbage | Start seeds indoors (fall) | May 19 – Jun 18 |
| Cabbage | Transplant outdoors (fall) | Jun 18 – Jul 19 |
| Leaf lettuce | Sow outdoors (spring) | Apr 28 – Jul 14 |
| Leaf lettuce | Sow outdoors (fall) | Jun 18 – Aug 4 |
| Spinach | Sow outdoors (spring) | Apr 21 – Jun 4 |
| Spinach | Sow outdoors (fall) | Jul 5 – Aug 9 |
| Radishes | Sow outdoors (spring) | Apr 28 – Jun 18 |
| Radishes | Sow outdoors (fall) | Jun 18 – Aug 19 |
| Kale | Sow outdoors (spring) | May 15 – Jun 4 |
| Kale | Sow outdoors (fall) | Jun 11 – Jul 19 |
| Carrots | Sow outdoors (spring) | May 29 – Jul 14 |
| Carrots | Sow outdoors (fall) | May 19 – Jul 4 |
| Garlic | Plant outdoors (fall) | Sep 18 – Oct 19 |
Where these dates come from
ZIP code 86515 is matched to the NOAA station Window Rock Ap, AZ, 1.9 km away, at 6,739 ft elevation (39 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Window Rock Ap, AZ (used) | 6,739 ft | May 29 | Sep 28 |
| Gallup Muni Ap, NM | 6,471 ft | May 31 | Sep 28 |
| Gallup Sand & Gravel, NM | 6,577 ft | May 11 | Oct 7 |
| Ganado, AZ | 6,340 ft | May 15 | Oct 10 |
Frost dates near Window Rock
- Saint Michaels, AZ 86511 · last May 29, first Sep 28
- Fort Defiance, AZ 86504 · last May 29, first Sep 28
- Navajo, NM 87328 · last May 29, first Sep 28
- Mexican Springs, NM 87320 · last May 31, first Sep 28
- Mentmore, NM 87319 · last May 31, first Sep 28
- Gamerco, NM 87317 · last May 11, first Oct 7
- Gallup, NM 87302 · last May 31, first Sep 28
- Lupton, AZ 86508 · last May 31, first Sep 28
Frequently asked questions
- When is the last frost in Window Rock, AZ?
- For ZIP code 86515, the average last spring frost (32°F) is May 29, based on NOAA 1991-2020 climate normals for the Window Rock Ap, AZ weather station. There is a 1-in-10 chance of a frost after June 10.
- When is the first frost in Window Rock, AZ?
- The average first fall frost (32°F) is September 28. There is a 1-in-10 chance of frost by September 16, so tender plants are at risk from that point on.
- How long is the growing season in 86515?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 121 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.