Fall in zone 8bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 85621 (Nogales, 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, Nogales Intl AP, AZ (4 miles away).
- Average last spring frostMar 2050% chance of a 32°F freeze after this date
- Average first fall frostNov 1750% chance of a 32°F freeze by this date
- Growing season (frost-free)239 daysmedian, 32°F threshold
- USDA hardiness zone8b15 to 20°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
67°F 55°F or warmer
24-hour average · latest 64°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Elgin 5 S (27 mi), Walnut Gulch #1 (56 mi), Tucson 11 W (61 mi).
4-inch depth
67°F 55°F or warmer
24-hour average · latest 68°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Elgin 5 S (27 mi), Walnut Gulch #1 (56 mi), Tucson 11 W (61 mi).
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 85621 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 67°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent (annual bluegrass, winter weeds): window open as soil cools through the 70s and 60s.
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 5 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 22–Oct 20
- Radish: fall sowing Oct 6–20
- Garlic: fall sowing Oct 6–Nov 3
- Shallot: fall sowing Oct 6–Nov 3
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 17: 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 24 |
| 50% (the "average" last frost) | Mar 20 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 13 |
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) | Oct 30 |
| 50% (the "average" first frost) | Nov 17 |
| 90% (late: most years have frozen by now) | Dec 3 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 13 | Nov 5 |
| 32°F (freeze) | Mar 20 | Nov 17 |
| 28°F (hard freeze) | Feb 23 | Nov 30 |
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 85621
Dates count from your average last spring frost (Mar 20) and first fall frost (Nov 17). 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 23–Feb 6 | Mar 27–Apr 10 (transplant) | Jul 21–Aug 18 (transplant) |
| Pepper (sweet and hot) | Jan 9–23 | Apr 3–17 (transplant) | Jul 28–Aug 18 (transplant) |
| Eggplant | Jan 9–23 | Apr 3–17 (transplant) | Jul 28–Aug 18 (transplant) |
| Tomatillo | Jan 23–Feb 6 | Mar 27–Apr 10 (transplant) | – |
| Lettuce | Jan 23–Feb 6 | Feb 27–Mar 20 (transplant) Feb 20–Apr 3 (sow outdoors) | Sep 22–Oct 13 (transplant) Sep 8–Oct 6 (sowing) |
| Spinach | – | Feb 6–27 (sow outdoors) | Sep 22–Oct 13 (sowing) |
| Kale | Jan 23–Feb 6 | Feb 20–Mar 6 (transplant) Feb 20–Mar 6 (sow outdoors) | Aug 25–Sep 22 (transplant) Aug 11–Sep 8 (sowing) |
| Collards | Jan 23–Feb 6 | Feb 20–Mar 20 (transplant) Feb 20–Mar 20 (sow outdoors) | Aug 25–Sep 22 (transplant) Aug 11–Sep 8 (sowing) |
| Broccoli | Jan 9–23 | Feb 20–Mar 6 (transplant) | Aug 11–Sep 8 (transplant) |
| Cabbage | Jan 9–23 | Feb 20–Mar 6 (transplant) | Aug 11–Sep 8 (transplant) |
| Cauliflower | Jan 9–23 | Mar 6–20 (transplant) | Aug 11–Sep 8 (transplant) |
| Brussels sprouts | Dec 26–Jan 9 | Feb 20–Mar 6 (transplant) | Jul 28–Aug 18 (transplant) |
| Kohlrabi | Jan 23–Feb 6 | Feb 20–Mar 6 (transplant) Feb 20–Mar 6 (sow outdoors) | Sep 8–22 (sowing) |
| Bok choy / Asian greens | – | Feb 20–Mar 6 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Arugula | – | Feb 20–Mar 20 (sow outdoors) | Sep 22–Oct 20 (sowing) |
| Mustard greens | – | Feb 20–Mar 13 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Swiss chard | Feb 6–20 | Mar 6–27 (transplant) Mar 6–Apr 3 (sow outdoors) | Sep 8–22 (sowing) |
| Beet | – | Feb 20–Mar 20 (sow outdoors) | Sep 8–22 (sowing) |
| Carrot | – | Feb 27–Mar 27 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Radish | – | Feb 13–Mar 27 (sow outdoors) | Oct 6–20 (sowing) |
| Turnip | – | Feb 20–Mar 13 (sow outdoors) | Sep 8–22 (sowing) |
| Parsnip | – | Feb 27–Mar 20 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 23–Feb 20 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Onion (bulbing) | Dec 26–Jan 9 | Feb 6–20 (transplant) | – |
| Green onion / scallion | – | Feb 6–Mar 6 (sow outdoors) | Sep 8–22 (sowing) |
| Leek | Dec 26–Jan 9 | Feb 20–Mar 6 (transplant) | – |
| Garlic | – | – | Oct 6–Nov 3 (sowing) |
| Shallot | – | Feb 6–20 (transplant) | Oct 6–Nov 3 (sowing) |
| Potato | – | Feb 20–Mar 6 (transplant) | Jul 28–Aug 11 (transplant) |
| Sweet potato | – | Apr 10–24 (transplant) | – |
| Sweet corn | – | Mar 27–Apr 10 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 27–Apr 10 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Bean, pole | – | Mar 27–Apr 10 (sow outdoors) | – |
| Lima bean | – | Apr 3–17 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 10–May 1 (sow outdoors) | – |
| Cucumber | Feb 20–27 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Summer squash / zucchini | Feb 20–27 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | Aug 25–Sep 8 (sowing) |
| Winter squash | Feb 20–27 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | – |
| Pumpkin | – | Mar 27–Apr 10 (sow outdoors) | – |
| Watermelon | Feb 20–27 | Apr 3–17 (transplant) Apr 3–17 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 20–27 | Apr 3–17 (transplant) Apr 3–17 (sow outdoors) | – |
| Okra | Feb 6–20 | Apr 3–17 (transplant) Apr 3–17 (sow outdoors) | – |
| Celery | Dec 26–Jan 9 | Mar 27–Apr 3 (transplant) | – |
| Basil | Feb 6–20 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | – |
| Cilantro | – | Mar 6–Apr 3 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Parsley | Jan 9–23 | Mar 6–20 (transplant) Feb 27–Mar 20 (sow outdoors) | – |
| Dill | – | Mar 20–Apr 3 (sow outdoors) | Sep 22–Oct 6 (sowing) |
| Sunflower | – | Mar 20–Apr 3 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 20–Mar 6 (transplant) | – |
| Rhubarb (crowns) | – | Feb 20–Mar 6 (transplant) | – |
| Strawberry (plants) | – | Feb 20–Mar 6 (transplant) | Sep 8–Oct 6 (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: Nogales Intl AP, AZ (NOAA GHCN-Daily ID USW00003196), elevation 3,932 ft, 3.9 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Nogales 6 N, AZ | 6 mi | Apr 16 | Nov 2 |
| Tumacacori Nm, AZ | 15 mi | Apr 5 | Nov 10 |
| Canelo 1 NW, AZ | 25 mi | Apr 23 | Oct 30 |
The average last-frost dates of these stations span 34 days, a rough guide to local variation. See data sources & methods.
Frost questions for 85621
When is the last frost in 85621?
The average (50% chance) last spring freeze of 32°F for ZIP 85621 is March 20. For a more cautious planting date, use April 13, when only 1 year in 10 still sees a later freeze.
When is the first frost in 85621?
The average first fall freeze is November 17. In 1 year in 10 it comes by October 30.
What hardiness zone is 85621?
ZIP 85621 is in USDA zone 8b (15 to 20°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 85621 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
85648 Rio Rico 85624 Patagonia 85640 Tumacacori-Carmen 85646 Tubac 85645 Elephant Head 85637 Sonoita 85601 Arivaca 85611 Elgin
Other ZIP codes in Santa Cruz County
85611 85624 85637 85640 85646 85648 All Santa Cruz 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.