Frost Line Depth in Sunnyvale, California
- 5 verified codes nearby
- Checked Oct 2026
No official local value
Frost rarely reaches the ground in Sunnyvale.
Nearby official codes require 5–12 in (5 verified codes).
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, Moffett Federal Airfield, 1.8 mi).
Checked Oct 2026. Report a correction
Does Sunnyvale have an official frost line depth?
No adopted frost line depth found for Sunnyvale in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 5 to 12 in. Use the deepest of them until the building department confirms Sunnyvale’s own number.
What frost line depth does Sunnyvale use for footings under Table R301.2(1)? Is it 5 in, like Palo Alto?
How deep do footings, decks and water lines need to be in Sunnyvale?
Drawn with the deepest nearby official value (12 in). Confirm Sunnyvale’s own depth before you dig.
House or garage footing in Sunnyvale: 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 Sunnyvale?
- J
- F
- M
- A
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- D
Sunnyvale never averages a low below freezing. 2 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 42.1 °F.
NOAA 1991–2020 climate normals, Moffett Federal Airfield station, 1.8 mi away, elevation 39 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 42.4 | 44.5 | 46.7 | 48.9 | 52.5 | 55.7 | 58.5 | 59 | 57.3 | 53.1 | 46.3 | 42.1 |
| High | 59 | 61.8 | 65 | 68 | 71.7 | 75.9 | 76.9 | 76.9 | 77.7 | 74.1 | 65.5 | 58.9 |
Sunnyvale 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 Sunnyvale use?
5 official codes near Sunnyvale are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Palo Alto | 5 in | 6 mi away |
| Campbell | 12 in | 8 mi away |
| Dublin | 12 in | 24 mi away |
| Santa Cruz | 12 in | 28 mi away |
| Watsonville | 12 in | 35 mi away |
How likely is the soil in Sunnyvale to heave?
USDA rates the sampled soil around Sunnyvale as 100% none for frost action (main soils: Urban land, Hangerone, Campbell).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Sunnyvale at a glance
- Frost line depth
- No official local value
- County
- Santa Clara County
- Population (2023 est.)
- 151,967
- Mean annual temperature
- 59.9 °F
- ZIP codes (10)
- 94024 · 94043 · 94085 · 94086 · 94087 · 94089 · 95002 · 95014 · 95051 · 95054