Frost Line Depth in La Mesa, California
- 1 verified code nearby
- Checked Oct 2026
No official local value
Frost rarely reaches the ground in La Mesa.
Nearby official codes require 12 in (1 verified code).
Footings still go at least 12 in (30 cm) below undisturbed ground (IRC R403.1.4).
Source and how we checked
We searched this place’s own code and website and found no published frost line depth.
Climate: 2 nights a year at or below 32 °F (NOAA 1991–2020, El Cajon, 5.9 mi).
Checked Oct 2026. Report a correction
Does La Mesa have an official frost line depth?
No adopted frost line depth found for La Mesa 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 La Mesa’s own number.
What frost line depth does La Mesa use for footings under Table R301.2(1)? Is it 12 in, like Mission Viejo?
How deep do footings, decks and water lines need to be in La Mesa?
Drawn with the deepest nearby official value (12 in). Confirm La Mesa’s own depth before you dig.
House or garage footing in La Mesa: 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 La Mesa?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
La Mesa never averages a low below freezing. 2 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 41.7 °F.
NOAA 1991–2020 climate normals, El Cajon station, 5.9 mi away, elevation 495 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 42.5 | 44.4 | 48 | 50.7 | 55.9 | 59.4 | 63.3 | 64.7 | 62.1 | 55.6 | 47.1 | 41.7 |
| High | 69.3 | 69.2 | 71.3 | 74.5 | 76.2 | 80.8 | 86.1 | 88.6 | 87.3 | 81 | 75.2 | 68.5 |
La Mesa has fewer freezing nights than 114 of the 208 other California places we track. The California median is 3. Coldest: El Dorado County; mildest: San Diego.
What frost line depth do towns near La Mesa use?
One official code near La Mesa is verified.
| Place | Verified frost line | Distance |
|---|---|---|
| Mission Viejo | 12 in | 69 mi away |
How likely is the soil in La Mesa to heave?
USDA rates the sampled soil around La Mesa as 22% none, 78% low for frost action (main soils: Redding, Urban land, Cieneba).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
La Mesa at a glance
- Frost line depth
- No official local value
- County
- San Diego County
- Population (2023 est.)
- 60,537
- Mean annual temperature
- 65.1 °F
- ZIP codes (4)
- 91941 · 91942 · 92115 · 92120