Climatic Data for Frost Protected Shallow Foundations

Maps

The 100-year return period of the Air Freezing Index (AFI) for the continental United States, Alaska, Hawaii, and Puerto Rico can be interpolated from analyzed maps given below. Data for 3,110 cites were used in these map analyses. The actual 100-year return period AFI value for these cities can be obtained from data tables. There is also documentation available on the procedures used to compute the Mean Annual Temperature map.

Cautionary Note when using Air Freezing Index values: Topographic variability, proximity to bodies of water, and urban heat effects should be considered when using these data. For those locations or if the planned construction site is not located nearby a station that has AFI data, using a combination of the AFI map and the most representative city(s) AFI value(s) is advisable.

AFI Maps (click on image for larger view)

Air-Freezing Index map - Alaska; Click here for a larger image. Air-Freezing Index map - Simplified; Click here for a larger image. Air-Freezing Index map - USA; Click here for a larger image. Mean Annual Temperature - USA; Click here for a larger image.

This page was developed as a parternership among the National Climatic Data Center, National Association of Home Builders Research Center, and American Society of Civil Engineers.