Frost Line Depth in Mount Vernon, New York
- Mount Vernon’s adopted code
- Checked Oct 2026
- Sources
Verified
42in
107 cm · 3 ft 6 in
Set in the building code Mount Vernon has adopted.
Source and how we checked
Document: mountvernonny.gov
Climate: 67 nights a year at or below 32 °F (NOAA 1991–2020, Bronx, 5.4 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Mount Vernon?
Mount Vernon's building authority sets the frost line depth at 42 in (107 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 Mount Vernon?
New York leaves the frost line depth to each city or county, and Mount Vernon fills it in when it adopts the residential code. The value above comes from Mount Vernon’s own document on mountvernonny.gov. See how New York sets frost line depth.
How deep do footings, decks and water lines need to be in Mount Vernon?
House or garage footing in Mount Vernon: dig at least 42 in (107 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 42 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 42 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 48 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 42 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 Mount Vernon?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Average lows are at or below freezing from Jan to Feb. 67 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 27.3 °F.
NOAA 1991–2020 climate normals, Bronx station, 5.4 mi away, elevation 39 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 27.3 | 28.7 | 34.6 | 44.4 | 54.6 | 64.3 | 70.6 | 69.1 | 62.1 | 50.7 | 41.3 | 33.1 |
| High | 39.7 | 42.6 | 50.3 | 61.4 | 72.3 | 80.9 | 86.1 | 84.1 | 77.1 | 65.8 | 54.1 | 44.8 |
Mount Vernon has fewer freezing nights than 65 of the 67 other New York places we track. The New York median is 141. Coldest: Franklin County; mildest: Kings County.
How likely is the soil in Mount Vernon to heave?
USDA rates the sampled soil around Mount Vernon as 9% low, 85% moderate, 6% high for frost action (main soils: Paxton, Charlton, Greenbelt).
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 Mount Vernon?
Mount Vernon at a glance
- Frost line depth
- 42 in
- County
- Westchester County
- Population (2023 est.)
- 71,168
- Mean annual temperature
- 55.8 °F
- ZIP codes (5)
- 10550 · 10552 · 10553 · 10708 · 10803