‘Local climate zones’ (LCZs) comprise a new and systematic classification of field sites for heat island studies. The classification divides urban and rural landscapes into 17 standard classes, each defined by structural and land cover properties that influence air temperature at screen height. This study is the first to evaluate the conceptual division of LCZs with temperature observations and simulation results from surface–atmosphere models. Results confirm that thermal contrasts exist among all LCZ classes, and that such contrasts are governed largely by building height and spacing, pervious surface fraction, tree density, and soil wetness. Therefore, partitioning of landscapes into structural and land cover classes, or ‘LCZs,’ is deemed justified for the purposes of field site classification in heat island studies. Also justified is the use of inter-zone temperature difference (ΔTLCZ X−Y) to quantify heat island magnitude. To further improve the LCZ system, we encourage other researchers to observe and model the climatic conditions of its varied classes. Especially useful would be tests using field data from different urban and rural environments to those in this study, and running more advanced urban canopy models with demonstrated predictive capability.