Frost dates for 85138Maricopa, AZ
The average last spring frost in Maricopa is February 23 and the average first fall frost is November 24, giving a typical growing season of about 274 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Feb 23
- Average first fall frost
- Nov 24
- Growing season
- 274 days
Safer after Mar 15 (1-in-10 risk)
Possible by Nov 10 (1-in-10 risk)
First frost typically in 28 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) | Feb 24 · Mar 12 · Apr 10 | Oct 27 · Nov 14 · Nov 28 | 243 days | 100% |
| Frost / freeze (32°F) | Jan 29 · Feb 23 · Mar 15 | Nov 10 · Nov 24 · Dec 8 | 274 days | 100% |
| Hard freeze (28°F) | Dec 31 · Feb 2 · Feb 28 | Nov 21 · Dec 6 · Dec 23 | 310 days | 99% |
Planting calendar for Maricopa
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 | Jan 23 – Mar 31 |
| Tomatoes | Transplant outdoors | Mar 11 – Aug 4 |
| Peppers | Start seeds indoors | Jan 23 – Feb 23 |
| Peppers | Transplant outdoors | Mar 25 – Apr 25 |
| Eggplant | Start seeds indoors | Feb 9 – Mar 10 |
| Eggplant | Transplant outdoors | Mar 25 – Apr 25 |
| Cucumbers | Sow outdoors | Mar 25 – Aug 14 |
| Summer squash | Sow outdoors | Mar 11 – Apr 25 |
| Winter squash & pumpkins | Sow outdoors | Mar 25 – Apr 25 |
| Snap beans | Sow outdoors | Mar 11 – Sep 6 |
| Sweet corn | Sow outdoors | Mar 11 – Aug 4 |
| Watermelon & cantaloupe | Sow outdoors | Mar 25 – Apr 25 |
| Okra | Sow outdoors | Mar 18 – Apr 10 |
| Peas | Sow outdoors (spring) | Jan 23 – Mar 10 |
| Potatoes | Plant outdoors (spring) | Jan 23 – Mar 25 |
| Onions | Start seeds indoors (spring) | Dec 12 – Jan 8 |
| Onions | Transplant outdoors (spring) | Feb 9 – Mar 10 |
| Broccoli | Start seeds indoors (spring) | Jan 5 – Feb 8 |
| Broccoli | Transplant outdoors (spring) | Feb 9 – Mar 10 |
| Broccoli | Start seeds indoors (fall) | Jul 25 – Aug 4 |
| Broccoli | Transplant outdoors (fall) | Aug 24 – Sep 4 |
| Cabbage | Start seeds indoors (spring) | Dec 26 – Jan 23 |
| Cabbage | Transplant outdoors (spring) | Jan 23 – Feb 23 |
| Cabbage | Start seeds indoors (fall) | Jul 15 – Aug 14 |
| Cabbage | Transplant outdoors (fall) | Aug 14 – Sep 14 |
| Leaf lettuce | Sow outdoors (spring) | Jan 23 – Apr 10 |
| Leaf lettuce | Sow outdoors (fall) | Aug 14 – Sep 30 |
| Spinach | Sow outdoors (spring) | Jan 16 – Mar 1 |
| Spinach | Sow outdoors (fall) | Aug 31 – Oct 5 |
| Radishes | Sow outdoors (spring) | Jan 23 – Mar 15 |
| Radishes | Sow outdoors (fall) | Aug 14 – Oct 15 |
| Kale | Sow outdoors (spring) | Feb 9 – Mar 1 |
| Kale | Sow outdoors (fall) | Aug 7 – Sep 14 |
| Carrots | Sow outdoors (spring) | Feb 23 – Apr 10 |
| Carrots | Sow outdoors (fall) | Jul 15 – Aug 30 |
| Garlic | Plant outdoors (fall) | Nov 14 – Dec 15 |
Where these dates come from
ZIP code 85138 is matched to the NOAA station Maricopa 4 N, AZ, 15 km away, at 1,160 ft elevation (100 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Maricopa 4 N, AZ (used) | 1,160 ft | Feb 23 | Nov 24 |
| Casa Grande, AZ | 1,400 ft | Feb 5 | Dec 6 |
| Chandler Heights, AZ | 1,425 ft | Feb 1 | Dec 11 |
| Robson Rch, AZ | 1,495 ft | Feb 7 | Dec 3 |
Frost dates near Maricopa
- Maricopa, AZ 85139 · last Feb 23, first Nov 24
- Stanfield, AZ 85172 · last Feb 5, first Dec 6
- Bapchule, AZ 85121 · last Feb 23, first Nov 24
- Casa Grande, AZ 85193 · last Feb 5, first Dec 6
- Sacaton, AZ 85147 · last Feb 17, first Nov 29
- Chandler, AZ 85248 · last Feb 13, first Dec 5
- Chandler Heights, AZ 85127 · last Feb 1, first Dec 11
- Gilbert, AZ 85298 · last Feb 1, first Dec 11
Frequently asked questions
- When is the last frost in Maricopa, AZ?
- For ZIP code 85138, the average last spring frost (32°F) is February 23, based on NOAA 1991-2020 climate normals for the Maricopa 4 N, AZ weather station. There is a 1-in-10 chance of a frost after March 15.
- When is the first frost in Maricopa, AZ?
- The average first fall frost (32°F) is November 24. There is a 1-in-10 chance of frost by November 10, so tender plants are at risk from that point on.
- How long is the growing season in 85138?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 274 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.