Frost Line Depth in Smyrna, Tennessee
- 4 verified codes nearby
- Checked Oct 2026
No official local value
No official frost line depth is published for Smyrna.
Nearby official codes require 10–12 in (4 verified codes).
Source and how we checked
We searched this place’s own code and website and found no published frost line depth.
Climate: 102 nights a year at or below 32 °F (NOAA 1991–2020, Smyrna 6S, 4.4 mi).
Checked Oct 2026. Report a correction
Does Smyrna have an official frost line depth?
No adopted frost line depth found for Smyrna in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 10 to 12 in. Use the deepest of them until the building department confirms Smyrna’s own number.
What frost line depth does Smyrna use for footings under Table R301.2(1)? Is it 12 in, like Murfreesboro?
How deep do footings, decks and water lines need to be in Smyrna?
Drawn with the deepest nearby official value (12 in). Confirm Smyrna’s own depth before you dig.
House or garage footing in Smyrna: dig at least 12 in (30 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 12 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 12 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 18 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 12 in | No code rule; common practice is below the frost line |
Work out posts, concrete and footing sizes with the fence post depth calculator or the deck footing calculator.
How cold does it get in Smyrna?
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Average lows are at or below freezing from Dec to Feb. 102 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 26.4 °F.
NOAA 1991–2020 climate normals, Smyrna 6s station, 4.4 mi away, elevation 550 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 26.4 | 28.8 | 35 | 43.8 | 52.8 | 61.3 | 65.7 | 64 | 56.4 | 44 | 33.4 | 29.6 |
| High | 48.1 | 52.3 | 61.3 | 71.3 | 79 | 86.2 | 89.7 | 90 | 84.6 | 73.3 | 60.8 | 51.5 |
Smyrna has more freezing nights than 55 of the 59 other Tennessee places we track. The Tennessee median is 84. Coldest: Greene County; mildest: Memphis.
What frost line depth do towns near Smyrna use?
4 official codes near Smyrna are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Murfreesboro | 12 in | 10 mi away |
| Hendersonville | 12 in | 24 mi away |
| Cheatham County | 12 in | 38 mi away |
| Maury County | 10 in | 39 mi away |
How likely is the soil in Smyrna to heave?
USDA rates the sampled soil around Smyrna as 100% none for frost action (main soils: Cumberland, Bradyville, Talbott).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Smyrna at a glance
- Frost line depth
- No official local value
- County
- Rutherford County
- Population (2023 est.)
- 57,418
- Mean annual temperature
- 57.9 °F
- ZIP codes (5)
- 37014 · 37086 · 37129 · 37135 · 37167