Fall in zone 8bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 85638 (Tombstone, 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, Tombstone, AZ (3 miles away).
- Average last spring frostMar 450% chance of a 32°F freeze after this date
- Average first fall frostNov 2950% chance of a 32°F freeze by this date
- Growing season (frost-free)264 daysmedian, 32°F threshold
- USDA hardiness zone8b15 to 20°F avg. coldest night
Get The Dial for 85638 (Tombstone)
Frost and freeze alerts from the NWS forecast for 85638, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.
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 65°F, as of Oct 18, 2:00 AM CDT
Measured at USDA NRCS SCAN station Walnut Gulch #1, 5 mi away. Daily averages: Thu 70°, Fri 70°, Sat 67°.
4-inch depth
68°F 55°F or warmer
24-hour average · latest 69°F, as of Oct 18, 2:00 AM CDT
Measured at USDA NRCS SCAN station Walnut Gulch #1, 5 mi away. Daily averages: Thu 71°, Fri 72°, Sat 68°.
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 85638 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 68°F at 4 inches. 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 Apr 19 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 sowing Sep 20–Oct 18
- Lettuce: fall transplant Oct 4–25
- Spinach: fall sowing Oct 4–25
- Bok choy / Asian greens: fall sowing Oct 4–18
- Arugula: fall sowing Oct 4–Nov 1
- Mustard greens: fall sowing Oct 4–18
- Radish: fall sowing Oct 18–Nov 1
- Garlic: fall sowing Oct 18–Nov 15
- Shallot: fall sowing Oct 18–Nov 15
- Cilantro: fall sowing Oct 4–18
- Dill: fall sowing Oct 4–18
- Strawberry (plants): fall transplant Sep 20–Oct 18
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 29: 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 3 |
| 50% (the "average" last frost) | Mar 4 |
| 10% (cautious: only 1 year in 10 freezes later) | Mar 31 |
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 12 |
| 50% (the "average" first frost) | Nov 29 |
| 90% (late: most years have frozen by now) | Dec 17 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Mar 29 | Nov 17 |
| 32°F (freeze) | Mar 4 | Nov 29 |
| 28°F (hard freeze) | Feb 8 | Dec 12 |
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 85638
Dates count from your average last spring frost (Mar 4) and first fall frost (Nov 29). 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 7–21 | Mar 11–25 (transplant) | Aug 2–30 (transplant) |
| Pepper (sweet and hot) | Dec 24–Jan 7 | Mar 18–Apr 1 (transplant) | Aug 9–30 (transplant) |
| Eggplant | Dec 24–Jan 7 | Mar 18–Apr 1 (transplant) | Aug 9–30 (transplant) |
| Tomatillo | Jan 7–21 | Mar 11–25 (transplant) | – |
| Lettuce | Jan 7–21 | Feb 11–Mar 4 (transplant) Feb 4–Mar 18 (sow outdoors) | Oct 4–25 (transplant) Sep 20–Oct 18 (sowing) |
| Spinach | – | Jan 21–Feb 11 (sow outdoors) | Oct 4–25 (sowing) |
| Kale | Jan 7–21 | Feb 4–18 (transplant) Feb 4–18 (sow outdoors) | Sep 6–Oct 4 (transplant) Aug 23–Sep 20 (sowing) |
| Collards | Jan 7–21 | Feb 4–Mar 4 (transplant) Feb 4–Mar 4 (sow outdoors) | Sep 6–Oct 4 (transplant) Aug 23–Sep 20 (sowing) |
| Broccoli | Dec 24–Jan 7 | Feb 4–18 (transplant) | Aug 23–Sep 20 (transplant) |
| Cabbage | Dec 24–Jan 7 | Feb 4–18 (transplant) | Aug 23–Sep 20 (transplant) |
| Cauliflower | Dec 24–Jan 7 | Feb 18–Mar 4 (transplant) | Aug 23–Sep 20 (transplant) |
| Brussels sprouts | Dec 10–24 | Feb 4–18 (transplant) | Aug 9–30 (transplant) |
| Kohlrabi | Jan 7–21 | Feb 4–18 (transplant) Feb 4–18 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Bok choy / Asian greens | – | Feb 4–18 (sow outdoors) | Oct 4–18 (sowing) |
| Arugula | – | Feb 4–Mar 4 (sow outdoors) | Oct 4–Nov 1 (sowing) |
| Mustard greens | – | Feb 4–25 (sow outdoors) | Oct 4–18 (sowing) |
| Swiss chard | Jan 21–Feb 4 | Feb 18–Mar 11 (transplant) Feb 18–Mar 18 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Beet | – | Feb 4–Mar 4 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Carrot | – | Feb 11–Mar 11 (sow outdoors) | Sep 6–20 (sowing) |
| Radish | – | Jan 28–Mar 11 (sow outdoors) | Oct 18–Nov 1 (sowing) |
| Turnip | – | Feb 4–25 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Parsnip | – | Feb 11–Mar 4 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 7–Feb 4 (sow outdoors) | Sep 6–20 (sowing) |
| Onion (bulbing) | Dec 10–24 | Jan 21–Feb 4 (transplant) | – |
| Green onion / scallion | – | Jan 21–Feb 18 (sow outdoors) | Sep 20–Oct 4 (sowing) |
| Leek | Dec 10–24 | Feb 4–18 (transplant) | – |
| Garlic | – | – | Oct 18–Nov 15 (sowing) |
| Shallot | – | Jan 21–Feb 4 (transplant) | Oct 18–Nov 15 (sowing) |
| Potato | – | Feb 4–18 (transplant) | Aug 9–23 (transplant) |
| Sweet potato | – | Mar 25–Apr 8 (transplant) | – |
| Sweet corn | – | Mar 11–25 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 11–25 (sow outdoors) | Sep 6–20 (sowing) |
| Bean, pole | – | Mar 11–25 (sow outdoors) | – |
| Lima bean | – | Mar 18–Apr 1 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Mar 25–Apr 15 (sow outdoors) | – |
| Cucumber | Feb 4–11 | Mar 11–25 (transplant) Mar 11–25 (sow outdoors) | Sep 6–20 (sowing) |
| Summer squash / zucchini | Feb 4–11 | Mar 11–25 (transplant) Mar 11–25 (sow outdoors) | Sep 6–20 (sowing) |
| Winter squash | Feb 4–11 | Mar 11–25 (transplant) Mar 11–25 (sow outdoors) | – |
| Pumpkin | – | Mar 11–25 (sow outdoors) | – |
| Watermelon | Feb 4–11 | Mar 18–Apr 1 (transplant) Mar 18–Apr 1 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 4–11 | Mar 18–Apr 1 (transplant) Mar 18–Apr 1 (sow outdoors) | – |
| Okra | Jan 21–Feb 4 | Mar 18–Apr 1 (transplant) Mar 18–Apr 1 (sow outdoors) | – |
| Celery | Dec 10–24 | Mar 11–18 (transplant) | – |
| Basil | Jan 21–Feb 4 | Mar 11–25 (transplant) Mar 11–25 (sow outdoors) | – |
| Cilantro | – | Feb 18–Mar 18 (sow outdoors) | Oct 4–18 (sowing) |
| Parsley | Dec 24–Jan 7 | Feb 18–Mar 4 (transplant) Feb 11–Mar 4 (sow outdoors) | – |
| Dill | – | Mar 4–18 (sow outdoors) | Oct 4–18 (sowing) |
| Sunflower | – | Mar 4–18 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 4–18 (transplant) | – |
| Rhubarb (crowns) | – | Feb 4–18 (transplant) | – |
| Strawberry (plants) | – | Feb 4–18 (transplant) | Sep 20–Oct 18 (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: Tombstone, AZ (NOAA GHCN-Daily ID USC00028619), elevation 4,659 ft, 3.2 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Sierra Vista, AZ | 16 mi | Apr 5 | Nov 9 |
| Bisbee 1WNW, AZ | 17 mi | Apr 1 | Nov 10 |
| Benson 6SE, AZ | 18 mi | Apr 12 | Nov 1 |
The average last-frost dates of these stations span 39 days, a rough guide to local variation. See data sources & methods.
Frost questions for 85638
When is the last frost in 85638?
The average (50% chance) last spring freeze of 32°F for ZIP 85638 is March 4. For a more cautious planting date, use March 31, when only 1 year in 10 still sees a later freeze.
When is the first frost in 85638?
The average first fall freeze is November 29. In 1 year in 10 it comes by November 12.
What hardiness zone is 85638?
ZIP 85638 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 85638 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
85635 Sierra Vista 85650 Sierra Vista Southeast 85616 Whetstone 85630 Benson 85603 Bisbee 85615 Sierra Vista Southeast 85617 McNeal 85613 Sierra Vista
Other ZIP codes in Cochise County
85602 85603 85605 85606 85607 85608 85609 85610 85613 85615 85616 85617 85620 85625 85626 85627 85630 85632 85635 85650 All Cochise County frost dates · Arizona frost dates
Never miss a frost: get The Dial
Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.