The guidance in this publication consists of generic definitions and methodologies for the characterization of extreme weather and climate events. This publication contribute to ensuring consistent exchange of information that underpins the WMO State of the Climate Reports, Climate Watches, climate change studies and other emerging applications. The purpose of the present guidelines is not to change the practice at the national level. Instead, it provides guidance for generic definitions, which are useful in contributing to WMO State of the Climate reports, climate watches, climate change studies and other emerging applications, including the recently adopted methodology for cataloguing hazardous events (WMO-CHE). These applications require regional and/or international exchange of information on extreme events.