Frost dates for 85601Arivaca, AZ
The average last spring frost in Arivaca is March 21 and the average first fall frost is November 20, giving a typical growing season of about 246 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 21
- Average first fall frost
- Nov 20
- Growing season
- 246 days
Safer after Apr 14 (1-in-10 risk)
Possible by Nov 1 (1-in-10 risk)
First frost typically in 24 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) | Mar 25 · Apr 14 · May 3 | Oct 24 · Nov 8 · Nov 24 | 207 days | 100% |
| Frost / freeze (32°F) | Feb 23 · Mar 21 · Apr 14 | Nov 1 · Nov 20 · Dec 7 | 246 days | 100% |
| Hard freeze (28°F) | Jan 15 · Feb 20 · Mar 19 | Nov 14 · Dec 3 · Dec 23 | 288 days | 100% |
Planting calendar for Arivaca
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 | Feb 18 – Apr 26 |
| Tomatoes | Transplant outdoors | Apr 6 – Jul 31 |
| Peppers | Start seeds indoors | Feb 18 – Mar 21 |
| Peppers | Transplant outdoors | Apr 20 – May 21 |
| Eggplant | Start seeds indoors | Mar 7 – Apr 5 |
| Eggplant | Transplant outdoors | Apr 20 – May 21 |
| Cucumbers | Sow outdoors | Apr 20 – Aug 10 |
| Summer squash | Sow outdoors | Apr 6 – May 21 |
| Winter squash & pumpkins | Sow outdoors | Apr 20 – May 21 |
| Snap beans | Sow outdoors | Apr 6 – Sep 2 |
| Sweet corn | Sow outdoors | Apr 6 – Jul 31 |
| Watermelon & cantaloupe | Sow outdoors | Apr 20 – May 21 |
| Okra | Sow outdoors | Apr 13 – May 6 |
| Peas | Sow outdoors (spring) | Feb 18 – Apr 5 |
| Potatoes | Plant outdoors (spring) | Feb 18 – Apr 20 |
| Onions | Start seeds indoors (spring) | Jan 7 – Feb 3 |
| Onions | Transplant outdoors (spring) | Mar 7 – Apr 5 |
| Broccoli | Start seeds indoors (spring) | Jan 31 – Mar 6 |
| Broccoli | Transplant outdoors (spring) | Mar 7 – Apr 5 |
| Broccoli | Start seeds indoors (fall) | Jul 21 – Jul 31 |
| Broccoli | Transplant outdoors (fall) | Aug 20 – Aug 31 |
| Cabbage | Start seeds indoors (spring) | Jan 21 – Feb 18 |
| Cabbage | Transplant outdoors (spring) | Feb 18 – Mar 21 |
| Cabbage | Start seeds indoors (fall) | Jul 11 – Aug 10 |
| Cabbage | Transplant outdoors (fall) | Aug 10 – Sep 10 |
| Leaf lettuce | Sow outdoors (spring) | Feb 18 – May 6 |
| Leaf lettuce | Sow outdoors (fall) | Aug 10 – Sep 26 |
| Spinach | Sow outdoors (spring) | Feb 11 – Mar 27 |
| Spinach | Sow outdoors (fall) | Aug 27 – Oct 1 |
| Radishes | Sow outdoors (spring) | Feb 18 – Apr 10 |
| Radishes | Sow outdoors (fall) | Aug 10 – Oct 11 |
| Kale | Sow outdoors (spring) | Mar 7 – Mar 27 |
| Kale | Sow outdoors (fall) | Aug 3 – Sep 10 |
| Carrots | Sow outdoors (spring) | Mar 21 – May 6 |
| Carrots | Sow outdoors (fall) | Jul 11 – Aug 26 |
| Garlic | Plant outdoors (fall) | Nov 10 – Dec 11 |
Where these dates come from
ZIP code 85601 is matched to the NOAA station Sasabe, AZ, 24.5 km away, at 3,590 ft elevation (157 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Sasabe, AZ (used) | 3,590 ft | Mar 21 | Nov 20 |
| Tumacacori Nm, AZ | 3,267 ft | Apr 5 | Nov 10 |
| Nogales 6 N, AZ | 3,461 ft | Apr 16 | Nov 2 |
| Anvil Rch, AZ | 2,759 ft | Mar 27 | Nov 9 |
Frost dates near Arivaca
- Amado, AZ 85645 · last Apr 5, first Nov 10
- Sasabe, AZ 85633 · last Mar 21, first Nov 20
- Rio Rico, AZ 85648 · last Mar 20, first Nov 17
- Tumacacori, AZ 85640 · last Apr 5, first Nov 10
- Tubac, AZ 85646 · last Apr 5, first Nov 10
- Green Valley, AZ 85622 · last Feb 25, first Nov 27
- Tucson, AZ 85736 · last Mar 27, first Nov 9
- Nogales, AZ 85628 · last Mar 20, first Nov 17
Frequently asked questions
- When is the last frost in Arivaca, AZ?
- For ZIP code 85601, the average last spring frost (32°F) is March 21, based on NOAA 1991-2020 climate normals for the Sasabe, AZ weather station. There is a 1-in-10 chance of a frost after April 14.
- When is the first frost in Arivaca, AZ?
- The average first fall frost (32°F) is November 20. There is a 1-in-10 chance of frost by November 1, so tender plants are at risk from that point on.
- How long is the growing season in 85601?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 246 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.