Oregon publishes no single frost depth for the whole state and does not leave the number to each town either; the Building Codes Division runs a Design Criteria Hub that returns the frost line depth for one specific site along with the rest of the Table R301.2 criteria, so a reader in Oregon looks the address up in that tool or asks the local building department for the printout.
Oregon publishes the frost line depth for one address at a time, through a tool the state runs itself.
The Oregon Design Criteria Hub is an interactive mapping tool that provides site-specific climatic and geographic design criteria for construction projects permitted using the Oregon Residential Specialty Code (ORSC) and the Oregon Structural Specialty Code (OSSC). The tool generates the site-specific climatic and geographic design criteria output in accordance with Table R301.2 of the ORSC.Oregon Design Criteria Hub, Oregon Building Codes Division, read September 22, 2026. Read it at the source
The state’s own tool is the authority here and it answers for one address at a time, which is why no single figure appears below for Oregon. The link above goes to it.
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. Bend is the coldest of the 3 cities on the record in Oregon.
184degree days
average freezing index a winter
Bend
| City | State | Freezing index | Once a century | Nights below freezing |
|---|---|---|---|---|
| Bend | Oregon | 184 | 622 | 180 |
| Portland | Oregon | 25 | 122 | 37 |
| Medford | Oregon | 19 | 106 | 75 |
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 Oregon marked at 76 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 North Carolina at 12 inches, Massachusetts at 4 feet and Connecticut at 42 inches. That is a reading of other states’ codes rather than a depth for an address in Oregon: soil, drainage, snow cover and local amendments all move the figure, and the building department issuing the permit is the office whose number binds.
Oregon code read September 22, 2026 from Oregon Design Criteria Hub, Oregon Building Codes Division. 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.