Frost Line Depth in Jefferson County, Alabama
- Alabama value from verified codes
- Checked Oct 2026
No official local value
No official frost line depth is published for Jefferson County.
No verified code nearby; every verified Alabama code we read uses 12 in.
Source and how we checked
We searched this place’s own code and website and found no published frost line depth.
Climate: 47 nights a year at or below 32 °F (NOAA 1991–2020, Birmingham Airport, 8.8 mi).
Checked Oct 2026. Report a correction
Does Jefferson County have an official frost line depth?
No adopted frost line depth found for Jefferson County in its official documents (checked Oct 2026). No verified code lies near Jefferson County; every Alabama code we verified uses 12 in. Ask the building department for Jefferson County’s own number before you dig.
What frost line depth does Jefferson County use for footings under Table R301.2(1)?
How deep do footings, decks and water lines need to be in Jefferson County?
Drawn with the deepest Alabama official value (12 in). Confirm Jefferson County’s own depth before you dig.
House or garage footing in Jefferson County: 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 Jefferson County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
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- D
Jefferson County never averages a low below freezing. 47 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 34.9 °F.
NOAA 1991–2020 climate normals, Birmingham Airport station, 8.8 mi away, elevation 615 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 34.9 | 38.4 | 45 | 52.1 | 61 | 68.5 | 72.1 | 71.3 | 65.3 | 53.9 | 43 | 37.9 |
| High | 54.5 | 59.1 | 67.1 | 75 | 82 | 88.1 | 91 | 90.6 | 85.9 | 76 | 65 | 56.9 |
Jefferson County has fewer freezing nights than 24 of the 39 other Alabama places we track. The Alabama median is 52. Coldest: Tallapoosa County; mildest: Mobile.
How likely is the soil in Jefferson County to heave?
USDA rates the sampled soil around Jefferson County as 100% none for frost action (main soils: Urban land, Nauvoo, Montevallo).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Jefferson County at a glance
- Frost line depth
- No official local value
- Population (2023 est.)
- 662,895
- Mean annual temperature
- 63.9 °F
- ZIP codes (64)
- 35005 · 35006 · 35020 · 35022 · 35023 · 35036 · 35060 · 35061 · 35062 · 35063 · 35064 · 35068 · 35071 · 35073 · 35079 · 35080 · 35091 · 35094 · 35111 · 35116 · 35117 · 35118 · 35119 · 35126 · 35127 · 35130 · 35146 · 35148 · 35172 · 35173 · 35180 · 35181 · 35203 · 35204 · 35205 · 35206 · 35207 · 35208 · 35209 · 35210 · 35211 · 35212 · 35213 · 35214 · 35215 · 35216 · 35217 · 35218 · 35221 · 35222 · 35223 · 35224 · 35226 · 35228 · 35229 · 35233 · 35234 · 35235 · 35242 · 35243 · 35244 · 35249 · 35254 · 35444