Frost Line Depth in Glendora, California
- Glendora’s adopted code
- Checked Oct 2026
- Sources
Verified
12in
30 cm · 1 ft
Set in the building code Glendora has adopted.
Source and how we checked
Document: cityofglendora.gov
Climate: 3 nights a year at or below 32 °F (NOAA 1991–2020, Pomona/Fairplex, 6.4 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Glendora?
Glendora's building authority sets the frost line depth at 12 in (30 cm). Footings, piers and other permanent supports must reach at least this depth (IRC R403.1.4.1).
Who sets the frost line depth in Glendora?
California leaves the frost line depth to each city or county, and Glendora fills it in when it adopts the residential code. The value above comes from Glendora’s own document on cityofglendora.gov. See how California sets frost line depth.
How deep do footings, decks and water lines need to be in Glendora?
House or garage footing in Glendora: 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 Glendora?
- J
- F
- M
- A
- M
- J
- J
- A
- S
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- N
- D
Glendora never averages a low below freezing. 3 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 41.5 °F.
NOAA 1991–2020 climate normals, Pomona/Fairplex station, 6.4 mi away, elevation 999 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 43.1 | 44.5 | 47 | 49.6 | 54 | 57.2 | 62.3 | 62.7 | 60.4 | 53.9 | 47 | 41.5 |
| High | 67.9 | 67.3 | 72 | 75.8 | 78.4 | 84.3 | 90.3 | 92.4 | 88.7 | 80.5 | 73.5 | 66.9 |
Glendora has fewer freezing nights than 99 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 Glendora use?
5 official codes near Glendora are verified; each links to its document.
How likely is the soil in Glendora to heave?
USDA rates the sampled soil around Glendora as 100% none for frost action (main soils: Caperton family, Trigo family, Tujunga).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
How do you confirm the frost line before you dig in Glendora?
Glendora at a glance
- Frost line depth
- 12 in
- County
- Los Angeles County
- Population (2023 est.)
- 49,934
- Mean annual temperature
- 65 °F
- ZIP codes (5)
- 91702 · 91740 · 91741 · 91750 · 91773