Frost dates for 85534Duncan, AZ
The average last spring frost in Duncan is April 24 and the average first fall frost is October 25, giving a typical growing season of about 183 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 24
- Average first fall frost
- Oct 25
- Growing season
- 183 days
Safer after May 8 (1-in-10 risk)
Possible by Oct 11 (1-in-10 risk)
Last frost typically in 179 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 22 · May 5 · May 18 | Oct 4 · Oct 17 · Oct 29 | 164 days | 100% |
| Frost / freeze (32°F) | Apr 8 · Apr 24 · May 8 | Oct 11 · Oct 25 · Nov 5 | 183 days | 100% |
| Hard freeze (28°F) | Mar 16 · Apr 7 · Apr 27 | Oct 20 · Nov 2 · Nov 15 | 206 days | 100% |
Planting calendar for Duncan
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 24 – May 30 |
| Tomatoes | Transplant outdoors | May 10 – Jul 5 |
| Peppers | Start seeds indoors | Mar 24 – Apr 24 |
| Peppers | Transplant outdoors | May 24 – Jun 24 |
| Eggplant | Start seeds indoors | Apr 10 – May 9 |
| Eggplant | Transplant outdoors | May 24 – Jun 24 |
| Cucumbers | Sow outdoors | May 24 – Jul 15 |
| Summer squash | Sow outdoors | May 10 – Jun 24 |
| Winter squash & pumpkins | Sow outdoors | May 24 – Jun 24 |
| Snap beans | Sow outdoors | May 10 – Aug 7 |
| Sweet corn | Sow outdoors | May 10 – Jul 5 |
| Watermelon & cantaloupe | Sow outdoors | May 24 – Jun 24 |
| Okra | Sow outdoors | May 17 – Jun 9 |
| Peas | Sow outdoors (spring) | Mar 24 – May 9 |
| Potatoes | Plant outdoors (spring) | Mar 24 – May 24 |
| Onions | Start seeds indoors (spring) | Feb 10 – Mar 9 |
| Onions | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (spring) | Mar 6 – Apr 9 |
| Broccoli | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (fall) | Jun 25 – Jul 5 |
| Broccoli | Transplant outdoors (fall) | Jul 25 – Aug 5 |
| Cabbage | Start seeds indoors (spring) | Feb 24 – Mar 24 |
| Cabbage | Transplant outdoors (spring) | Mar 24 – Apr 24 |
| Cabbage | Start seeds indoors (fall) | Jun 15 – Jul 15 |
| Cabbage | Transplant outdoors (fall) | Jul 15 – Aug 15 |
| Leaf lettuce | Sow outdoors (spring) | Mar 24 – Jun 9 |
| Leaf lettuce | Sow outdoors (fall) | Jul 15 – Aug 31 |
| Spinach | Sow outdoors (spring) | Mar 17 – Apr 30 |
| Spinach | Sow outdoors (fall) | Aug 1 – Sep 5 |
| Radishes | Sow outdoors (spring) | Mar 24 – May 14 |
| Radishes | Sow outdoors (fall) | Jul 15 – Sep 15 |
| Kale | Sow outdoors (spring) | Apr 10 – Apr 30 |
| Kale | Sow outdoors (fall) | Jul 8 – Aug 15 |
| Carrots | Sow outdoors (spring) | Apr 24 – Jun 9 |
| Carrots | Sow outdoors (fall) | Jun 15 – Jul 31 |
| Garlic | Plant outdoors (fall) | Oct 15 – Nov 15 |
Where these dates come from
ZIP code 85534 is matched to the NOAA station Duncan, AZ, 17.2 km away, at 3,660 ft elevation (182 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Duncan, AZ (used) | 3,660 ft | Apr 24 | Oct 25 |
| Clifton, AZ | 3,520 ft | Feb 26 | Nov 23 |
| Safford Muni Ap, AZ | 3,176 ft | Mar 8 | Nov 20 |
| Safford Ag Ctr, AZ | 2,954 ft | Mar 25 | Nov 9 |
Frost dates near Duncan
- Morenci, AZ 85540 · last May 6, first Oct 18
- Clifton, AZ 85533 · last May 6, first Oct 18
- Mule Creek, NM 88051 · last May 26, first Oct 5
- Safford, AZ 85546 · last Mar 25, first Nov 9
- Solomon, AZ 85551 · last Mar 25, first Nov 9
- Redrock, NM 88055 · last Apr 30, first Oct 23
- Thatcher, AZ 85552 · last Mar 25, first Nov 9
- Buckhorn, NM 88025 · last May 9, first Oct 15
Frequently asked questions
- When is the last frost in Duncan, AZ?
- For ZIP code 85534, the average last spring frost (32°F) is April 24, based on NOAA 1991-2020 climate normals for the Duncan, AZ weather station. There is a 1-in-10 chance of a frost after May 8.
- When is the first frost in Duncan, AZ?
- The average first fall frost (32°F) is October 25. There is a 1-in-10 chance of frost by October 11, so tender plants are at risk from that point on.
- How long is the growing season in 85534?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 183 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.