Fall in zone 9aPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 85138 (Maricopa, AZ)
Average last spring and first fall frost dates with 10%, 50% and 90% odds, from NOAA's 1991–2020 climate normals for the nearest weather station, Maricopa 4 N, AZ (7 miles away).
- Average last spring frostFeb 2350% chance of a 32°F freeze after this date
- Average first fall frostNov 2450% chance of a 32°F freeze by this date
- Growing season (frost-free)274 daysmedian, 32°F threshold
- USDA hardiness zone9a20 to 25°F avg. coldest night
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This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
No soil station with a fresh reading within 62 miles.
4-inch depth
No soil station with a fresh reading within 62 miles.
Fall: Texas A&M AgriLife times fall pre-emergent (for winter weeds such as annual bluegrass) to soil cooling to about 70°F for several days. The 50–55°F band is the spring trigger. Always read and follow the product label.
7-day forecast and frost risk
The latest National Weather Service 7-day forecast and any Frost Advisory or Freeze Warning for 85138 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
No soil reading near this ZIP. Typical extension timing for your region: spring late January to February; fall September to October.
Fertilizer window
Lawn region: Arid Southwest (low desert). Timing only; always follow the product label.
- Bermudagrass (warm-season): Spring: Several weeks after the lawn is fully green (April–May) (about Apr 10 here, using green-up about 3–4 weeks after your average last frost); Summer: Every 4–6 weeks through mid-August (heaviest feeder of the group); Late: Light, low-nitrogen/high-potassium feeding about 4 weeks before first frost, or skip. Avoid: Heavy late-fall nitrogen (linked to spring dead spot).
- Perennial ryegrass (cool-season): Early fall: September; Late fall: October–November; Overseeded Bermuda: Light feeding once the winter rye is established, if needed. Avoid: Summer feeding.
Plant now
- Lettuce: fall transplant Sep 29–Oct 20
- Spinach: fall sowing Sep 29–Oct 20
- Arugula: fall sowing Sep 29–Oct 27
- Radish: fall sowing Oct 13–27
- Garlic: fall sowing Oct 13–Nov 10
- Shallot: fall sowing Oct 13–Nov 10
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 24: skip heavy pruning in the 6–8 weeks before it, because new growth may not harden off in time.
Spring-flowering shrubs are pruned right after their flowers fade, not by date. See the pruning guide.
Last spring frost odds
| Chance of a 32°F freeze after this date | Date |
|---|---|
| 90% (early: most years still freeze after this) | Jan 29 |
| 50% (the "average" last frost) | Feb 23 |
| 10% (cautious: only 1 year in 10 freezes later) | Mar 15 |
Most gardeners plant frost-tender crops (tomatoes, peppers, basil) after the 50% date, and closer to the 10% date for less risk.
First fall frost odds
| Chance the first 32°F freeze has happened by this date | Date |
|---|---|
| 10% (early: 1 year in 10 freezes this soon) | Nov 10 |
| 50% (the "average" first frost) | Nov 24 |
| 90% (late: most years have frozen by now) | Dec 8 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Mar 12 | Nov 14 |
| 32°F (freeze) | Feb 23 | Nov 24 |
| 28°F (hard freeze) | Feb 2 | Dec 6 |
n/a means NOAA did not publish a date at that threshold for this station (usually because it rarely gets that cold).
Vegetable planting calendar for 85138
Dates count from your average last spring frost (Feb 23) and first fall frost (Nov 24). Half of years have a frost after the spring date, so give tender crops (tomatoes, peppers, squash) some slack.
| Crop | Start indoors | Spring planting | Fall planting |
|---|---|---|---|
| Tomato | Dec 29–Jan 12 | Mar 2–16 (transplant) | Jul 28–Aug 25 (transplant) |
| Pepper (sweet and hot) | Dec 15–29 | Mar 9–23 (transplant) | Aug 4–25 (transplant) |
| Eggplant | Dec 15–29 | Mar 9–23 (transplant) | Aug 4–25 (transplant) |
| Tomatillo | Dec 29–Jan 12 | Mar 2–16 (transplant) | – |
| Lettuce | Dec 29–Jan 12 | Feb 2–23 (transplant) Jan 26–Mar 9 (sow outdoors) | Sep 29–Oct 20 (transplant) Sep 15–Oct 13 (sowing) |
| Spinach | – | Jan 12–Feb 2 (sow outdoors) | Sep 29–Oct 20 (sowing) |
| Kale | Dec 29–Jan 12 | Jan 26–Feb 9 (transplant) Jan 26–Feb 9 (sow outdoors) | Sep 1–29 (transplant) Aug 18–Sep 15 (sowing) |
| Collards | Dec 29–Jan 12 | Jan 26–Feb 23 (transplant) Jan 26–Feb 23 (sow outdoors) | Sep 1–29 (transplant) Aug 18–Sep 15 (sowing) |
| Broccoli | Dec 15–29 | Jan 26–Feb 9 (transplant) | Aug 18–Sep 15 (transplant) |
| Cabbage | Dec 15–29 | Jan 26–Feb 9 (transplant) | Aug 18–Sep 15 (transplant) |
| Cauliflower | Dec 15–29 | Feb 9–23 (transplant) | Aug 18–Sep 15 (transplant) |
| Brussels sprouts | Dec 1–15 | Jan 26–Feb 9 (transplant) | Aug 4–25 (transplant) |
| Kohlrabi | Dec 29–Jan 12 | Jan 26–Feb 9 (transplant) Jan 26–Feb 9 (sow outdoors) | Sep 15–29 (sowing) |
| Bok choy / Asian greens | – | Jan 26–Feb 9 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Arugula | – | Jan 26–Feb 23 (sow outdoors) | Sep 29–Oct 27 (sowing) |
| Mustard greens | – | Jan 26–Feb 16 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Swiss chard | Jan 12–26 | Feb 9–Mar 2 (transplant) Feb 9–Mar 9 (sow outdoors) | Sep 15–29 (sowing) |
| Beet | – | Jan 26–Feb 23 (sow outdoors) | Sep 15–29 (sowing) |
| Carrot | – | Feb 2–Mar 2 (sow outdoors) | Sep 1–15 (sowing) |
| Radish | – | Jan 19–Mar 2 (sow outdoors) | Oct 13–27 (sowing) |
| Turnip | – | Jan 26–Feb 16 (sow outdoors) | Sep 15–29 (sowing) |
| Parsnip | – | Feb 2–23 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Dec 29–Jan 26 (sow outdoors) | Sep 1–15 (sowing) |
| Onion (bulbing) | Dec 1–15 | Jan 12–26 (transplant) | – |
| Green onion / scallion | – | Jan 12–Feb 9 (sow outdoors) | Sep 15–29 (sowing) |
| Leek | Dec 1–15 | Jan 26–Feb 9 (transplant) | – |
| Garlic | – | – | Oct 13–Nov 10 (sowing) |
| Shallot | – | Jan 12–26 (transplant) | Oct 13–Nov 10 (sowing) |
| Potato | – | Jan 26–Feb 9 (transplant) | Aug 4–18 (transplant) |
| Sweet potato | – | Mar 16–30 (transplant) | – |
| Sweet corn | – | Mar 2–16 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 2–16 (sow outdoors) | Sep 1–15 (sowing) |
| Bean, pole | – | Mar 2–16 (sow outdoors) | – |
| Lima bean | – | Mar 9–23 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Mar 16–Apr 6 (sow outdoors) | – |
| Cucumber | Jan 26–Feb 2 | Mar 2–16 (transplant) Mar 2–16 (sow outdoors) | Sep 1–15 (sowing) |
| Summer squash / zucchini | Jan 26–Feb 2 | Mar 2–16 (transplant) Mar 2–16 (sow outdoors) | Sep 1–15 (sowing) |
| Winter squash | Jan 26–Feb 2 | Mar 2–16 (transplant) Mar 2–16 (sow outdoors) | – |
| Pumpkin | – | Mar 2–16 (sow outdoors) | – |
| Watermelon | Jan 26–Feb 2 | Mar 9–23 (transplant) Mar 9–23 (sow outdoors) | – |
| Cantaloupe / muskmelon | Jan 26–Feb 2 | Mar 9–23 (transplant) Mar 9–23 (sow outdoors) | – |
| Okra | Jan 12–26 | Mar 9–23 (transplant) Mar 9–23 (sow outdoors) | – |
| Celery | Dec 1–15 | Mar 2–9 (transplant) | – |
| Basil | Jan 12–26 | Mar 2–16 (transplant) Mar 2–16 (sow outdoors) | – |
| Cilantro | – | Feb 9–Mar 9 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Parsley | Dec 15–29 | Feb 9–23 (transplant) Feb 2–23 (sow outdoors) | – |
| Dill | – | Feb 23–Mar 9 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Sunflower | – | Feb 23–Mar 9 (sow outdoors) | – |
| Asparagus (crowns) | – | Jan 26–Feb 9 (transplant) | – |
| Rhubarb (crowns) | – | Jan 26–Feb 9 (transplant) | – |
| Strawberry (plants) | – | Jan 26–Feb 9 (transplant) | Sep 15–Oct 13 (transplant) |
Typical ranges from university extension planting calendars, adjusted to your frost dates. Probabilities, not guarantees. Fall windows that would overlap spring planting are left out, as are fall crops of frost-tender plants where the frost-free season is under 210 days.
Where these numbers come from
Station: Maricopa 4 N, AZ (NOAA GHCN-Daily ID USC00025270), elevation 1,160 ft, 7.0 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Casa Grande, AZ | 18 mi | Feb 5 | Dec 6 |
| Chandler Heights, AZ | 22 mi | Feb 1 | Dec 11 |
| Laveen 3 SSE, AZ | 24 mi | Jan 14 | Dec 22 |
The average last-frost dates of these stations span 40 days, a rough guide to local variation. See data sources & methods.
Frost questions for 85138
When is the last frost in 85138?
The average (50% chance) last spring freeze of 32°F for ZIP 85138 is February 23. For a more cautious planting date, use March 15, when only 1 year in 10 still sees a later freeze.
When is the first frost in 85138?
The average first fall freeze is November 24. In 1 year in 10 it comes by November 10.
What hardiness zone is 85138?
ZIP 85138 is in USDA zone 9a (20 to 25°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 85138 right now?
This page shows the latest 2-inch and 4-inch soil temperature from the nearest public soil station (USDA SCAN, NOAA USCRN or TexMesonet), or a labeled estimate when no station is close, against the 50–55°F spring pre-emergent band.
Nearby ZIP codes
85172 Stanfield 85121 Casa Blanca 85139 Goodyear 85248 Chandler 85122 Casa Grande 85147 Sacaton 85193 Casa Grande 85339 Phoenix
Other ZIP codes in Pinal County
85118 85119 85120 85121 85122 85123 85128 85131 85132 85137 85139 85140 85141 85142 85143 85145 85147 85172 85173 85191 85192 85193 85194 85618 All Pinal County frost dates · Arizona frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
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Free. One weekly email plus alerts when your ZIP has a frost or a soil-temperature change worth acting on. After you submit, Kit (our email provider) sends a confirmation email: check your email and click the link to confirm. You aren't subscribed until you do. We collect only your email address and ZIP, sent to Kit to deliver The Dial. Unsubscribe anytime.