Frost Line Depth in Mobile County, Alabama
- 1 verified code nearby
- Checked Oct 2026
No official local value
No official frost line depth is published for Mobile County.
Nearby official codes require 12 in (1 verified code).
Source and how we checked
We searched this place’s own code and website and found no published frost line depth.
Climate: 21 nights a year at or below 32 °F (NOAA 1991–2020, Mobile, 2.6 mi).
Checked Oct 2026. Report a correction
Does Mobile County have an official frost line depth?
No adopted frost line depth found for Mobile County in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 12 in. Use the deepest of them until the building department confirms Mobile County’s own number.
What frost line depth does Mobile County use for footings under Table R301.2(1)? Is it 12 in, like Mobile?
How deep do footings, decks and water lines need to be in Mobile County?
Drawn with the deepest nearby official value (12 in). Confirm Mobile County’s own depth before you dig.
House or garage footing in Mobile 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 Mobile County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Mobile County never averages a low below freezing. 21 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 40.7 °F.
NOAA 1991–2020 climate normals, Mobile station, 2.6 mi away, elevation 208 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 40.7 | 44.4 | 50 | 56 | 63.8 | 70.8 | 73.1 | 72.9 | 68.8 | 58.2 | 47.7 | 43 |
| High | 61.5 | 65.6 | 71.8 | 77.8 | 84.9 | 89.4 | 90.9 | 90.8 | 87.5 | 79.7 | 70.2 | 63.5 |
Mobile County has fewer freezing nights than 36 of the 39 other Alabama places we track. The Alabama median is 52. Coldest: Tallapoosa County; mildest: Mobile.
What frost line depth do towns near Mobile County use?
One official code near Mobile County is verified.
| Place | Verified frost line | Distance |
|---|---|---|
| Mobile | 12 in | 6 mi away |
How likely is the soil in Mobile County to heave?
USDA rates the sampled soil around Mobile County as 100% none for frost action (main soils: Wadley, Benndale, Malbis).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Mobile County at a glance
- Frost line depth
- No official local value
- Population (2023 est.)
- 411,640
- Mean annual temperature
- 67.6 °F
- ZIP codes (39)
- 36505 · 36509 · 36512 · 36513 · 36521 · 36522 · 36523 · 36525 · 36528 · 36541 · 36544 · 36560 · 36568 · 36571 · 36572 · 36575 · 36582 · 36587 · 36602 · 36603 · 36604 · 36605 · 36606 · 36607 · 36608 · 36609 · 36610 · 36611 · 36612 · 36613 · 36615 · 36617 · 36618 · 36619 · 36652 · 36663 · 36688 · 36693 · 36695