TM 5-852-1/AFR 88-19, Volume 1
GENERAL AIR INDEX INFORMATION FOR NORTH AMERICA AND EURASIA
The freezing and thawing index data presented here are for general information only and are not sufficiently
precise in local detail for use in selecting values to be employed in design at a particular site. Such values should be
computed directly from meteorological records of weather observation stations nearest to the proposed site.
Figure A-1 shows the mean air freezing indexes for North America and northern Eurasia, and figure A-2 shows the
mean air thawing indexes. The largest mean air freezing indexes in Siberia, about 12,500 Fahrenheit degree-days, are of
the same magnitudes as the largest in North America, about 13,000 Fahrenheit degree-days. On the other hand, air
thawing indexes in much of the same coldest areas of Siberia are larger than in northern Canada and Greenland.
Figures A-3 and A-4 show design air freezing index and design air thawing index values, in North America,
computed for pavement design in accordance with the definitions in paragraphs 1-4c(6) and 1-4c(7).