Frost dates for 85646Tubac, AZ
The average last spring frost in Tubac is April 5 and the average first fall frost is November 10, giving a typical growing season of about 217 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 5
- Average first fall frost
- Nov 10
- Growing season
- 217 days
Safer after Apr 25 (1-in-10 risk)
Possible by Oct 21 (1-in-10 risk)
First frost typically in 7 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 6 · Apr 23 · May 9 | Oct 13 · Oct 30 · Nov 14 | 190 days | 100% |
| Frost / freeze (32°F) | Mar 13 · Apr 5 · Apr 25 | Oct 21 · Nov 10 · Nov 27 | 217 days | 100% |
| Hard freeze (28°F) | Feb 16 · Mar 12 · Apr 8 | Nov 1 · Nov 20 · Dec 9 | 251 days | 100% |
Planting calendar for Tubac
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 5 – May 11 |
| Tomatoes | Transplant outdoors | Apr 21 – Jul 21 |
| Peppers | Start seeds indoors | Mar 5 – Apr 5 |
| Peppers | Transplant outdoors | May 5 – Jun 5 |
| Eggplant | Start seeds indoors | Mar 22 – Apr 20 |
| Eggplant | Transplant outdoors | May 5 – Jun 5 |
| Cucumbers | Sow outdoors | May 5 – Jul 31 |
| Summer squash | Sow outdoors | Apr 21 – Jun 5 |
| Winter squash & pumpkins | Sow outdoors | May 5 – Jun 5 |
| Snap beans | Sow outdoors | Apr 21 – Aug 23 |
| Sweet corn | Sow outdoors | Apr 21 – Jul 21 |
| Watermelon & cantaloupe | Sow outdoors | May 5 – Jun 5 |
| Okra | Sow outdoors | Apr 28 – May 21 |
| Peas | Sow outdoors (spring) | Mar 5 – Apr 20 |
| Potatoes | Plant outdoors (spring) | Mar 5 – May 5 |
| Onions | Start seeds indoors (spring) | Jan 22 – Feb 18 |
| Onions | Transplant outdoors (spring) | Mar 22 – Apr 20 |
| Broccoli | Start seeds indoors (spring) | Feb 15 – Mar 21 |
| Broccoli | Transplant outdoors (spring) | Mar 22 – Apr 20 |
| Broccoli | Start seeds indoors (fall) | Jul 11 – Jul 21 |
| Broccoli | Transplant outdoors (fall) | Aug 10 – Aug 21 |
| Cabbage | Start seeds indoors (spring) | Feb 5 – Mar 5 |
| Cabbage | Transplant outdoors (spring) | Mar 5 – Apr 5 |
| Cabbage | Start seeds indoors (fall) | Jul 1 – Jul 31 |
| Cabbage | Transplant outdoors (fall) | Jul 31 – Aug 31 |
| Leaf lettuce | Sow outdoors (spring) | Mar 5 – May 21 |
| Leaf lettuce | Sow outdoors (fall) | Jul 31 – Sep 16 |
| Spinach | Sow outdoors (spring) | Feb 26 – Apr 11 |
| Spinach | Sow outdoors (fall) | Aug 17 – Sep 21 |
| Radishes | Sow outdoors (spring) | Mar 5 – Apr 25 |
| Radishes | Sow outdoors (fall) | Jul 31 – Oct 1 |
| Kale | Sow outdoors (spring) | Mar 22 – Apr 11 |
| Kale | Sow outdoors (fall) | Jul 24 – Aug 31 |
| Carrots | Sow outdoors (spring) | Apr 5 – May 21 |
| Carrots | Sow outdoors (fall) | Jul 1 – Aug 16 |
| Garlic | Plant outdoors (fall) | Oct 31 – Dec 1 |
Where these dates come from
ZIP code 85646 is matched to the NOAA station Tumacacori Nm, AZ, 5 km away, at 3,267 ft elevation (55 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Tumacacori Nm, AZ (used) | 3,267 ft | Apr 5 | Nov 10 |
| Nogales 6 N, AZ | 3,461 ft | Apr 16 | Nov 2 |
| Santa Rita Exp Range, AZ | 4,300 ft | Feb 25 | Dec 5 |
| Nogales Intl Ap, AZ | 3,932 ft | Mar 20 | Nov 17 |
Frost dates near Tubac
- Tumacacori, AZ 85640 · last Apr 5, first Nov 10
- Amado, AZ 85645 · last Apr 5, first Nov 10
- Rio Rico, AZ 85648 · last Mar 20, first Nov 17
- Nogales, AZ 85628 · last Mar 20, first Nov 17
- Green Valley, AZ 85622 · last Feb 25, first Nov 27
- Arivaca, AZ 85601 · last Mar 21, first Nov 20
- Patagonia, AZ 85624 · last Apr 18, first Nov 1
- Sahuarita, AZ 85629 · last Feb 25, first Nov 27
Frequently asked questions
- When is the last frost in Tubac, AZ?
- For ZIP code 85646, the average last spring frost (32°F) is April 5, based on NOAA 1991-2020 climate normals for the Tumacacori Nm, AZ weather station. There is a 1-in-10 chance of a frost after April 25.
- When is the first frost in Tubac, AZ?
- The average first fall frost (32°F) is November 10. There is a 1-in-10 chance of frost by October 21, so tender plants are at risk from that point on.
- How long is the growing season in 85646?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 217 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.