This module provides an overview of climatology, the study of climate. The module begins by examining the drivers that combine to create the climate regions of the world—from those at the mesoscale (local) level to those at the synoptic-scale (continental) and global-scale levels. Examples include locally dominant winds, air masses, fronts, ocean currents, Earth’s rotation around the sun, and latitude. Each discussion of a climate driver has an ‘example/exploration’ segment, where the information is applied to several cities. The module also examines a scheme for classifying the world’s climate zones, the sources and uses of climate information, and some of its limitations. The module is intended for a wide range of users, from forecasters and scientists to those in business and government as well as the general public—in short, anyone interested in learning about climatology. Some familiarity with basic meteorology is useful although not required.