where does most of the precipitation on earth happen
Precipitation Precipitation is a major component of the water cycle, and is responsible for depositing the fresh water on the planet. Approximately 505,000 cubic kilometres (121,000 cu mi) of water falls as precipitation each year; 398,000 cubic kilometres (95,000 cu mi) of it over the oceans and 107,000 cubic kilometres (26,000 cu mi) over land.[5] Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres (39 in), but over land it is only 715 millimetres (28.1 in). Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes.
Climate of Ireland Rainfall is the most common form of precipitation on the island, and is extremely common throughout Ireland, although some parts of the west coast receive over four times as much rain as the east coast. Rainfall in Ireland normally comes from Atlantic frontal systems which travel northeast over the island, bringing cloud and rain. Most of the eastern half of the country has between 750 and 1,000 mm (29.5 and 39.4 in) of rainfall in the year. Rainfall in the west generally averages between 1,000 and 1,250 mm (39.4 and 49.2 in). In many mountainous districts rainfall exceeds 3,000 mm (118.1 in) per year. The wettest months almost everywhere are December and January. April is the driest month generally, but in many southern parts June is the driest.