West Virginia states no frost depth of its own; the State Building Code adopts the 2018 IRC and leaves the blanks that the model code marks for the jurisdiction, frost line depth among them, to each locality that adopts the code, so in the mountain counties a reader gets the number from the municipal or county building official, and where no local jurisdiction has adopted the code there is no enforced frost depth at all.
West Virginia leaves the frost line depth to the local building department, which is where the number for an address comes from.
7.3. Throughout the national codes, adopted in subsection 4.1 of this rule, there are discretionary provisions or amendments which require further action by the adopting local jurisdiction in order to adapt these codes to various local conditions. ... It is therefore the intent of this rule to further authorize each local jurisdiction to further complete, by order or ordinance, those respective areas which are indicated to be completed by the adopting “jurisdiction” and any of the appendices the local jurisdiction wishes to adopt.87CSR4 State Building Code, West Virginia State Fire Commission, 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 West Virginia 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. Elkins is the coldest of the 2 cities on the record in West Virginia.
322degree days
average freezing index a winter
Elkins-Randolph Co AP
| City | State | Freezing index | Once a century | Nights below freezing |
|---|---|---|---|---|
| Elkins | West Virginia | 322 | 948 | 141 |
| Charleston | West Virginia | 151 | 492 | 97 |
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 West Virginia marked at 237 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 Massachusetts at 4 feet, North Carolina at 12 inches and Connecticut at 42 inches. That is a reading of other states’ codes rather than a depth for an address in West Virginia: soil, drainage, snow cover and local amendments all move the figure, and the building department issuing the permit is the office whose number binds.
West Virginia code read September 22, 2026 from 87CSR4 State Building Code, West Virginia State Fire Commission. 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.