New York publishes no frost line depth of its own: it adopts the Residential Code of New York State whole and its state level amendments leave the climatic and geographic design criteria to the local jurisdiction, so the depth that governs a footing comes from the city, town or village building department, while the state DOT, for its own bridges, puts spread footings on soil at least 4 feet below finished ground to clear the deepest frost.
New York leaves the frost line depth to the local building department, which is where the number for an address comes from.
Incorporation by reference. The 2025 RCNYS is incorporated herein by reference.19 NYCRR Part 1220, Residential Construction, New York State Department of State, Division of Building Standards and Codes, read September 22, 2026. Read it at the source
That makes the building department issuing the permit the office with the number, and it is a short call: the counter gives the depth for the address, and the same call settles whether a deck footing or a slab edge needs a footing inspection before the concrete goes in. What New York does publish is below, and it is worth having in hand first.
The air freezing index is the quantity the frost provisions of the model codes are written on: add up how far each day’s mean temperature fell below freezing over a winter, in degree days, and take the deepest run the winter managed. It measures how much cold the ground had to absorb, which is why it is the honest way to set one place beside another. Lake Placid is the coldest of the 3 cities on the record in New York.
1,547degree days
average freezing index a winter
Lake Placid 2 S
| City | State | Freezing index | Once a century | Nights below freezing |
|---|---|---|---|---|
| Lake Placid | New York | 1,547 | 2,619 | 187 |
| Syracuse | New York | 659 | 1,518 | 134 |
| New York City | New York | 138 | 446 | 71 |
Computed from NOAA National Centers for Environmental Information, Global Historical Climatology Network daily temperature records for each station, from 1951 onward. These are measurements of winter, not depths.
Only a handful of states answer with one number for the whole state, and they are the only codes that can be set beside each other directly. Ranked by the freezing index at their own reference cities, with New York marked at 781 degree days for comparison against what those codes settled on:
Left to right, the mildest winters to the hardest. The figure on the right is what that state wrote into its code.
The nearest by winter are Connecticut at 42 inches, Michigan at 42 inches and Massachusetts at 4 feet. That is a reading of other states’ codes rather than a depth for an address in New York: soil, drainage, snow cover and local amendments all move the figure, and the building department issuing the permit is the office whose number binds.
New York code read September 22, 2026 from 19 NYCRR Part 1220, Residential Construction, New York State Department of State, Division of Building Standards and Codes. Codes are amended and a local amendment can be deeper than the state figure, so the building department issuing the permit has the number that binds. Every state is on the frost line depth hub.