Caltrans Pavement Climate Regions Map

Map of Caltrans Pavement Climate Regions

Map of California Pavement Climate Regions, (PDF)

What effects can climate have on pavement? What aspects of climate must be considered during pavement design and engineering?


Temperatures cause pavements to expand and contract, creating pressures that can cause pavements to buckle or crack. Binders in flexible pavements will also become softer at higher temperatures and more brittle at colder temperatures.


Precipitation can increase the potential for water to infiltrate the base and subbase layers thereby weakening their structural strength and increase susceptibility to erosion.


In freeze/thaw environments, the expansion and contraction of water as it freezes (in addition to the use of salts, sands, chains, and snow plows) create additional stress on pavements.

Solar Radiation

Solar radiation can also cause some pavements to oxidize.

Since the impact of climate varies depending on geographic location, the State has been divided into nine climate regions illustrated in the map below.

Read more about the impact of climate on pavements in the Highway Design Manual (HDM): Topic 615 - Climate.