CLIMAT is a code for reporting monthly climatological data assembled at land-based meteorological surface observation sites to data centres. CLIMAT-coded messages contain information on several meteorological variables that are important to monitor characteristics, changes, and variability of climate. Usually these messages are sent and exchanged via the Global Telecommunication System (GTS) of the World Meteorological Organisation (WMO). Modifications of the CLIMAT code are the CLIMAT SHIP and CLIMAT TEMP / CLIMAT TEMP SHIP codes which serve to report monthly climatological data assembled at ocean-based meteorological surface observation sites and at land-/ocean-based meteorological upper-air observation sites, respectively. The monthly values included usually are obtained by averaging observational values of one or several daily observations over the respective month.