  Environmental conditions in various regions can have a severely negative
impact on the longevity and durability of the civil engineering
infrastructures. In 2018, a published paper used 1971 to 2010 NOAA data from
the contiguous United States to examine the temporal changes in secondary
climate attributes (freeze-thaw cycles and freeze index) using the climate
normals from two time windows, 1971-2000 and 1981-2010. That paper investigated
whether there have been statistically significant changes in climate attribute
levels across the two time windows, and used GIS-based interpolation methods to
develop isarithmic maps of the climate attributes to facilitate their
interpretation and application. This paper updates that study. In this study,
we use NOAA climatic data from 1991 to 2020 to construct continuous surface
maps showing the values of the primary and secondary climate attributes at the
48 continental states. The new maps provide an updated picture of the freeze
index values and freeze-thaw cycles for the most recent climate condition.
These new values provide a better picture of the freezing season
characteristics of the United States, and will provide information necessary
for better winter maintenance procedures and infrastructure design to
accommodate regional climate differences.
