Fall in zone 7bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 37166 (Smithville, TN)
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, Smithville 2 SE, TN (2 miles away).
- Average last spring frostApr 1850% chance of a 32°F freeze after this date
- Average first fall frostOct 2250% chance of a 32°F freeze by this date
- Growing season (frost-free)187 daysmedian, 32°F threshold
- USDA hardiness zone7b5 to 10°F avg. coldest night
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Frost and freeze alerts from the NWS forecast for 37166, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
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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 37166 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 early March to early April; fall late August to mid-September.
Fertilizer window
Lawn region: Transition zone. Timing only; always follow the product label.
- Bermudagrass (warm-season): Spring: Several weeks after the lawn is fully green (April–May) (about Jun 3 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).
- Tall fescue (cool-season): Early fall: September (main feeding); Late fall: November, while still green; Late winter: Optional light feeding February–March. Avoid: Feeding after mid-spring and through summer in the transition zone (stress and brown patch).
Plant now
No vegetable planting windows are open this week.
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Oct 22: 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) | Apr 2 |
| 50% (the "average" last frost) | Apr 18 |
| 10% (cautious: only 1 year in 10 freezes later) | May 2 |
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 10 |
| 50% (the "average" first frost) | Oct 22 |
| 90% (late: most years have frozen by now) | Nov 4 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 30 | Oct 13 |
| 32°F (freeze) | Apr 18 | Oct 22 |
| 28°F (hard freeze) | Apr 4 | Nov 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 37166
Dates count from your average last spring frost (Apr 18) and first fall frost (Oct 22). 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 | Feb 21–Mar 7 | Apr 25–May 9 (transplant) | – |
| Pepper (sweet and hot) | Feb 7–21 | May 2–16 (transplant) | – |
| Eggplant | Feb 7–21 | May 2–16 (transplant) | – |
| Tomatillo | Feb 21–Mar 7 | Apr 25–May 9 (transplant) | – |
| Lettuce | Feb 21–Mar 7 | Mar 28–Apr 18 (transplant) Mar 21–May 2 (sow outdoors) | Aug 27–Sep 17 (transplant) Aug 13–Sep 10 (sowing) |
| Spinach | – | Mar 7–28 (sow outdoors) | Aug 27–Sep 17 (sowing) |
| Kale | Feb 21–Mar 7 | Mar 21–Apr 4 (transplant) Mar 21–Apr 4 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Collards | Feb 21–Mar 7 | Mar 21–Apr 18 (transplant) Mar 21–Apr 18 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Broccoli | Feb 7–21 | Mar 21–Apr 4 (transplant) | Jul 16–Aug 13 (transplant) |
| Cabbage | Feb 7–21 | Mar 21–Apr 4 (transplant) | Jul 16–Aug 13 (transplant) |
| Cauliflower | Feb 7–21 | Apr 4–18 (transplant) | Jul 16–Aug 13 (transplant) |
| Brussels sprouts | Jan 24–Feb 7 | Mar 21–Apr 4 (transplant) | Jul 2–23 (transplant) |
| Kohlrabi | Feb 21–Mar 7 | Mar 21–Apr 4 (transplant) Mar 21–Apr 4 (sow outdoors) | Aug 13–27 (sowing) |
| Bok choy / Asian greens | – | Mar 21–Apr 4 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Arugula | – | Mar 21–Apr 18 (sow outdoors) | Aug 27–Sep 24 (sowing) |
| Mustard greens | – | Mar 21–Apr 11 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Swiss chard | Mar 7–21 | Apr 4–25 (transplant) Apr 4–May 2 (sow outdoors) | Aug 13–27 (sowing) |
| Beet | – | Mar 21–Apr 18 (sow outdoors) | Aug 13–27 (sowing) |
| Carrot | – | Mar 28–Apr 25 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Radish | – | Mar 14–Apr 25 (sow outdoors) | Sep 10–24 (sowing) |
| Turnip | – | Mar 21–Apr 11 (sow outdoors) | Aug 13–27 (sowing) |
| Parsnip | – | Mar 28–Apr 18 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 21–Mar 21 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Onion (bulbing) | Jan 24–Feb 7 | Mar 7–21 (transplant) | – |
| Green onion / scallion | – | Mar 7–Apr 4 (sow outdoors) | Aug 13–27 (sowing) |
| Leek | Jan 24–Feb 7 | Mar 21–Apr 4 (transplant) | – |
| Garlic | – | – | Sep 10–Oct 8 (sowing) |
| Shallot | – | Mar 7–21 (transplant) | Sep 10–Oct 8 (sowing) |
| Potato | – | Mar 21–Apr 4 (transplant) | Jul 2–16 (transplant) |
| Sweet potato | – | May 9–23 (transplant) | – |
| Sweet corn | – | Apr 25–May 9 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 25–May 9 (sow outdoors) | – |
| Bean, pole | – | Apr 25–May 9 (sow outdoors) | – |
| Lima bean | – | May 2–16 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 9–30 (sow outdoors) | – |
| Cucumber | Mar 21–28 | Apr 25–May 9 (transplant) Apr 25–May 9 (sow outdoors) | – |
| Summer squash / zucchini | Mar 21–28 | Apr 25–May 9 (transplant) Apr 25–May 9 (sow outdoors) | – |
| Winter squash | Mar 21–28 | Apr 25–May 9 (transplant) Apr 25–May 9 (sow outdoors) | – |
| Pumpkin | – | Apr 25–May 9 (sow outdoors) | – |
| Watermelon | Mar 21–28 | May 2–16 (transplant) May 2–16 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 21–28 | May 2–16 (transplant) May 2–16 (sow outdoors) | – |
| Okra | Mar 7–21 | May 2–16 (transplant) May 2–16 (sow outdoors) | – |
| Celery | Jan 24–Feb 7 | Apr 25–May 2 (transplant) | – |
| Basil | Mar 7–21 | Apr 25–May 9 (transplant) Apr 25–May 9 (sow outdoors) | – |
| Cilantro | – | Apr 4–May 2 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Parsley | Feb 7–21 | Apr 4–18 (transplant) Mar 28–Apr 18 (sow outdoors) | – |
| Dill | – | Apr 18–May 2 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Sunflower | – | Apr 18–May 2 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 21–Apr 4 (transplant) | – |
| Rhubarb (crowns) | – | Mar 21–Apr 4 (transplant) | – |
| Strawberry (plants) | – | Mar 21–Apr 4 (transplant) | Aug 13–Sep 10 (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: Smithville 2 SE, TN (NOAA GHCN-Daily ID USC00408405), elevation 890 ft, 1.7 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Rock Island Sp, TN | 11 mi | Apr 6 | Oct 30 |
| Lancaster Edgar Evins Marina, TN | 12 mi | Apr 3 | Nov 4 |
| Mc Minnville, TN | 17 mi | Apr 7 | Oct 30 |
The average last-frost dates of these stations span 15 days, a rough guide to local variation. See data sources & methods.
Frost questions for 37166
When is the last frost in 37166?
The average (50% chance) last spring freeze of 32°F for ZIP 37166 is April 18. For a more cautious planting date, use May 2, when only 1 year in 10 still sees a later freeze.
When is the first frost in 37166?
The average first fall freeze is October 22. In 1 year in 10 it comes by October 10.
What hardiness zone is 37166?
ZIP 37166 is in USDA zone 7b (5 to 10°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 37166 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
37059 Dowelltown 37095 Liberty 38587 38582 38550 38569 38579 38544 Baxter
Other ZIP codes in DeKalb County
37012 37059 37095 All DeKalb County frost dates · Tennessee 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.