Pavement temperatures can be accurately quantified utilizing the Climatic-Materials-Structural (CMS) computer model developed at the University of Illinois. Required CMS inputs (for temperature modeling) are (a) thermal properties of materials and soils, (b) air temperature data, (c) solar radiation data, and (d) wind velocity data. In this paper the development and use of a comprehensive Illinois Climatic Data Base for Pavements are presented. Air temperature data are summarized on a weekly basis and solar radiation and wind velocity data are presented in the form of a monthly state map. Illustrative, applications-oriented examples are presented for (a) strength--degree-day curing relations for pozzolanic stabilized base materials, (b) asphalt concrete moduli--pavement temperature effects, and (c) temperature gradients in portland cement concrete slabs. The emphasis here is on the concepts and techniques used to establish the Illinois Climatic Data Base for Pavements. The illustrative information demonstrates the versatility and usefulness of the climatic data base and heat-transfer model procedures in pavement analysis and design. The procedures and techniques described can be used to establish a climatic data base for other states or locations. The climatic data base and heat-transfer model approach is recommended for quantifying temperature effects in flexible and rigid pavement analysis and design.