Frost dates for 85553Tonto Basin, AZ
The average last spring frost in Tonto Basin is March 7 and the average first fall frost is November 20, giving a typical growing season of about 255 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 7
- Average first fall frost
- Nov 20
- Growing season
- 255 days
Safer after Mar 27 (1-in-10 risk)
Possible by Nov 3 (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 11 · Mar 27 · Apr 16 | Oct 25 · Nov 10 · Nov 22 | 224 days | 100% |
| Frost / freeze (32°F) | Feb 13 · Mar 7 · Mar 27 | Nov 3 · Nov 20 · Dec 3 | 255 days | 100% |
| Hard freeze (28°F) | Jan 20 · Feb 15 · Mar 7 | Nov 16 · Dec 1 · Dec 17 | 286 days | 100% |
Planting calendar for Tonto Basin
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 4 – Apr 12 |
| Tomatoes | Transplant outdoors | Mar 23 – Jul 31 |
| Peppers | Start seeds indoors | Feb 4 – Mar 7 |
| Peppers | Transplant outdoors | Apr 6 – May 7 |
| Eggplant | Start seeds indoors | Feb 21 – Mar 22 |
| Eggplant | Transplant outdoors | Apr 6 – May 7 |
| Cucumbers | Sow outdoors | Apr 6 – Aug 10 |
| Summer squash | Sow outdoors | Mar 23 – May 7 |
| Winter squash & pumpkins | Sow outdoors | Apr 6 – May 7 |
| Snap beans | Sow outdoors | Mar 23 – Sep 2 |
| Sweet corn | Sow outdoors | Mar 23 – Jul 31 |
| Watermelon & cantaloupe | Sow outdoors | Apr 6 – May 7 |
| Okra | Sow outdoors | Mar 30 – Apr 22 |
| Peas | Sow outdoors (spring) | Feb 4 – Mar 22 |
| Potatoes | Plant outdoors (spring) | Feb 4 – Apr 6 |
| Onions | Start seeds indoors (spring) | Dec 24 – Jan 20 |
| Onions | Transplant outdoors (spring) | Feb 21 – Mar 22 |
| Broccoli | Start seeds indoors (spring) | Jan 17 – Feb 20 |
| Broccoli | Transplant outdoors (spring) | Feb 21 – Mar 22 |
| Broccoli | Start seeds indoors (fall) | Jul 21 – Jul 31 |
| Broccoli | Transplant outdoors (fall) | Aug 20 – Aug 31 |
| Cabbage | Start seeds indoors (spring) | Jan 7 – Feb 4 |
| Cabbage | Transplant outdoors (spring) | Feb 4 – Mar 7 |
| Cabbage | Start seeds indoors (fall) | Jul 11 – Aug 10 |
| Cabbage | Transplant outdoors (fall) | Aug 10 – Sep 10 |
| Leaf lettuce | Sow outdoors (spring) | Feb 4 – Apr 22 |
| Leaf lettuce | Sow outdoors (fall) | Aug 10 – Sep 26 |
| Spinach | Sow outdoors (spring) | Jan 28 – Mar 13 |
| Spinach | Sow outdoors (fall) | Aug 27 – Oct 1 |
| Radishes | Sow outdoors (spring) | Feb 4 – Mar 27 |
| Radishes | Sow outdoors (fall) | Aug 10 – Oct 11 |
| Kale | Sow outdoors (spring) | Feb 21 – Mar 13 |
| Kale | Sow outdoors (fall) | Aug 3 – Sep 10 |
| Carrots | Sow outdoors (spring) | Mar 7 – Apr 22 |
| Carrots | Sow outdoors (fall) | Jul 11 – Aug 26 |
| Garlic | Plant outdoors (fall) | Nov 10 – Dec 11 |
Where these dates come from
ZIP code 85553 is matched to the NOAA station Punkin Ctr, AZ, 2.9 km away, at 2,325 ft elevation (81 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Punkin Ctr, AZ (used) | 2,325 ft | Mar 7 | Nov 20 |
| Roosevelt 1 S, AZ | 2,605 ft | Jan 17 | Dec 25 |
| Mormon Flat, AZ | 1,705 ft | Jan 29 | Dec 24 |
| Stewart Mtn Dam, AZ | 1,422 ft | Feb 13 | Dec 5 |
Frost dates near Tonto Basin
- Tortilla Flat, AZ 85190 · last Feb 11, first Dec 10
- Roosevelt, AZ 85545 · last Jan 17, first Dec 25
- Rio Verde, AZ 85263 · last Jan 6, first Dec 28
- Young, AZ 85554 · last May 6, first Oct 20
- Payson, AZ 85541 · last Apr 29, first Oct 24
- Fort Mcdowell, AZ 85264 · last Jan 6, first Dec 28
- Scottsdale, AZ 85262 · last Jan 27, first Dec 21
- Fountain Hills, AZ 85269 · last Jan 6, first Dec 28
Frequently asked questions
- When is the last frost in Tonto Basin, AZ?
- For ZIP code 85553, the average last spring frost (32°F) is March 7, based on NOAA 1991-2020 climate normals for the Punkin Ctr, AZ weather station. There is a 1-in-10 chance of a frost after March 27.
- When is the first frost in Tonto Basin, AZ?
- The average first fall frost (32°F) is November 20. There is a 1-in-10 chance of frost by November 3, so tender plants are at risk from that point on.
- How long is the growing season in 85553?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 255 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.