The country with the highest rainfall worldwide is the South American nation of Colombia. Based on yearly average precipitation measurements collected between 2010 and 2014, Colombia received an average annual rainfall of 127.6 inches as reported by the World Bank Group. The African nation of Sao Tome and Principe is a close second with average annual rainfalls during the same time period reported as 126 inches.
Precipitation, or rain, is defined in meteorology as any form of water, liquid or solid, that falls from clouds. It is measured by the amount of rain water or snow collected in a cylinder-shaped plastic or metal rain gauge over a period of time. The highest recorded 12-month rainfall of 905 inches was measured in the village of Cherrapunji in Northeastern India in 1861. The town of Lloro, in Choco, Colombia, is a contender for the place with the highest rainfall on Earth because of its average annual rainfalls of about 520 inches.
Both the highest and the next to highest average rainfall countries are located within the equatorial zone. Rainfall in this region of the world is predictably greater than at higher or lower latitudes. This is because solar heating is most pronounced at the equator and evaporates much larger amounts of water into the atmosphere that return to the surface in the form of rainfall.