This paper intends to demonstrate that, on Terra's surface, there are cycles of air's temperature and of other meteorological elements having a duration of 19 years (the Metonic cycle). These 19-year cycles are recorded on every continent, especially in temperate climate areas where the (planetary) Rossby waves exhibit very clearly. As in the case of other cycles of meteorological elements, the atmospheric tides play a very important role in their occurrence. In the case of this cycle, the atmospheric tides are also generated mainly by Moon’s and Sun’s attraction.