Fall in zone 9aPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 85320 (Aguila, 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, Aguila, AZ (8 miles away).
- Average last spring frostMar 1750% chance of a 32°F freeze after this date
- Average first fall frostNov 1950% chance of a 32°F freeze by this date
- Growing season (frost-free)243 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 85320 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 May 2 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
- Arugula: fall sowing Sep 24–Oct 22
- Radish: fall sowing Oct 8–22
- Garlic: fall sowing Oct 8–Nov 5
- Shallot: fall sowing Oct 8–Nov 5
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 19: 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) | Feb 18 |
| 50% (the "average" last frost) | Mar 17 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 12 |
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 5 |
| 50% (the "average" first frost) | Nov 19 |
| 90% (late: most years have frozen by now) | Dec 1 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 7 | Nov 9 |
| 32°F (freeze) | Mar 17 | Nov 19 |
| 28°F (hard freeze) | Feb 19 | Dec 1 |
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 85320
Dates count from your average last spring frost (Mar 17) and first fall frost (Nov 19). 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 | Jan 20–Feb 3 | Mar 24–Apr 7 (transplant) | Jul 23–Aug 20 (transplant) |
| Pepper (sweet and hot) | Jan 6–20 | Mar 31–Apr 14 (transplant) | Jul 30–Aug 20 (transplant) |
| Eggplant | Jan 6–20 | Mar 31–Apr 14 (transplant) | Jul 30–Aug 20 (transplant) |
| Tomatillo | Jan 20–Feb 3 | Mar 24–Apr 7 (transplant) | – |
| Lettuce | Jan 20–Feb 3 | Feb 24–Mar 17 (transplant) Feb 17–Mar 31 (sow outdoors) | Sep 24–Oct 15 (transplant) Sep 10–Oct 8 (sowing) |
| Spinach | – | Feb 3–24 (sow outdoors) | Sep 24–Oct 15 (sowing) |
| Kale | Jan 20–Feb 3 | Feb 17–Mar 3 (transplant) Feb 17–Mar 3 (sow outdoors) | Aug 27–Sep 24 (transplant) Aug 13–Sep 10 (sowing) |
| Collards | Jan 20–Feb 3 | Feb 17–Mar 17 (transplant) Feb 17–Mar 17 (sow outdoors) | Aug 27–Sep 24 (transplant) Aug 13–Sep 10 (sowing) |
| Broccoli | Jan 6–20 | Feb 17–Mar 3 (transplant) | Aug 13–Sep 10 (transplant) |
| Cabbage | Jan 6–20 | Feb 17–Mar 3 (transplant) | Aug 13–Sep 10 (transplant) |
| Cauliflower | Jan 6–20 | Mar 3–17 (transplant) | Aug 13–Sep 10 (transplant) |
| Brussels sprouts | Dec 23–Jan 6 | Feb 17–Mar 3 (transplant) | Jul 30–Aug 20 (transplant) |
| Kohlrabi | Jan 20–Feb 3 | Feb 17–Mar 3 (transplant) Feb 17–Mar 3 (sow outdoors) | Sep 10–24 (sowing) |
| Bok choy / Asian greens | – | Feb 17–Mar 3 (sow outdoors) | Sep 24–Oct 8 (sowing) |
| Arugula | – | Feb 17–Mar 17 (sow outdoors) | Sep 24–Oct 22 (sowing) |
| Mustard greens | – | Feb 17–Mar 10 (sow outdoors) | Sep 24–Oct 8 (sowing) |
| Swiss chard | Feb 3–17 | Mar 3–24 (transplant) Mar 3–31 (sow outdoors) | Sep 10–24 (sowing) |
| Beet | – | Feb 17–Mar 17 (sow outdoors) | Sep 10–24 (sowing) |
| Carrot | – | Feb 24–Mar 24 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Radish | – | Feb 10–Mar 24 (sow outdoors) | Oct 8–22 (sowing) |
| Turnip | – | Feb 17–Mar 10 (sow outdoors) | Sep 10–24 (sowing) |
| Parsnip | – | Feb 24–Mar 17 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 20–Feb 17 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Onion (bulbing) | Dec 23–Jan 6 | Feb 3–17 (transplant) | – |
| Green onion / scallion | – | Feb 3–Mar 3 (sow outdoors) | Sep 10–24 (sowing) |
| Leek | Dec 23–Jan 6 | Feb 17–Mar 3 (transplant) | – |
| Garlic | – | – | Oct 8–Nov 5 (sowing) |
| Shallot | – | Feb 3–17 (transplant) | Oct 8–Nov 5 (sowing) |
| Potato | – | Feb 17–Mar 3 (transplant) | Jul 30–Aug 13 (transplant) |
| Sweet potato | – | Apr 7–21 (transplant) | – |
| Sweet corn | – | Mar 24–Apr 7 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 24–Apr 7 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Bean, pole | – | Mar 24–Apr 7 (sow outdoors) | – |
| Lima bean | – | Mar 31–Apr 14 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 7–28 (sow outdoors) | – |
| Cucumber | Feb 17–24 | Mar 24–Apr 7 (transplant) Mar 24–Apr 7 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Summer squash / zucchini | Feb 17–24 | Mar 24–Apr 7 (transplant) Mar 24–Apr 7 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Winter squash | Feb 17–24 | Mar 24–Apr 7 (transplant) Mar 24–Apr 7 (sow outdoors) | – |
| Pumpkin | – | Mar 24–Apr 7 (sow outdoors) | – |
| Watermelon | Feb 17–24 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 17–24 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | – |
| Okra | Feb 3–17 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | – |
| Celery | Dec 23–Jan 6 | Mar 24–31 (transplant) | – |
| Basil | Feb 3–17 | Mar 24–Apr 7 (transplant) Mar 24–Apr 7 (sow outdoors) | – |
| Cilantro | – | Mar 3–31 (sow outdoors) | Sep 24–Oct 8 (sowing) |
| Parsley | Jan 6–20 | Mar 3–17 (transplant) Feb 24–Mar 17 (sow outdoors) | – |
| Dill | – | Mar 17–31 (sow outdoors) | Sep 24–Oct 8 (sowing) |
| Sunflower | – | Mar 17–31 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 17–Mar 3 (transplant) | – |
| Rhubarb (crowns) | – | Feb 17–Mar 3 (transplant) | – |
| Strawberry (plants) | – | Feb 17–Mar 3 (transplant) | Sep 10–Oct 8 (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: Aguila, AZ (NOAA GHCN-Daily ID USC00020060), elevation 2,165 ft, 7.9 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Wickenburg, AZ | 30 mi | Mar 7 | Nov 20 |
| Alamo Dam, AZ | 34 mi | Mar 4 | Nov 23 |
| Wittmann 1SE, AZ | 41 mi | Feb 5 | Dec 11 |
The average last-frost dates of these stations span 43 days, a rough guide to local variation. See data sources & methods.
Frost questions for 85320
When is the last frost in 85320?
The average (50% chance) last spring freeze of 32°F for ZIP 85320 is March 17. For a more cautious planting date, use April 12, when only 1 year in 10 still sees a later freeze.
When is the first frost in 85320?
The average first fall freeze is November 19. In 1 year in 10 it comes by November 5.
What hardiness zone is 85320?
ZIP 85320 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 85320 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
85357 Alamo Lake 85390 Wickenburg 85348 Vicksburg 85354 Tonopah 85332 Congress 85361 Surprise 85396 Buckeye 85325 Bouse
Other ZIP codes in Maricopa County
85003 85004 85006 85007 85008 85009 85012 85013 85014 85015 85016 85017 85018 85019 85020 85021 85022 85023 85024 85026 85027 85028 85029 85031 All Maricopa County frost dates · Arizona frost dates
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- 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.