Mount Waialeale (Mount Waiʻaleʻale) at an elevation of 5,148 feet (1,569 m), is a shield Volcano and the second highest point on the island of Kauaʻi in the Hawaiian Islands. Averaging more than 452 inches (11,500 mm) of rain a year since 1912, with a record 683 inches (17,300 mm) in 1982, its summit is one of the rainiest spots on earth. Recent reports though mention that over the period 1978-2007 the wettest spot in Hawaii is Big Bog on Maui (404 inch per year), and that the rainfall in Hawaii is decreasing.
Climate and Rainfall Statistics:
The summit of Waiʻaleʻale features a tropical rainforest climate (Köppen Af), with substantial rainfall throughout the course of the year. (Bodin 1978: 272) quotes 11,684 millimetres (460.0 in) per year figure as being the 1912-45 average, an average that quite possibly will have changed since then, while The National Climatic Data Center quotes this figure as a 30 year average. The Weather Network and The Guinness Book of Weather Records (Holford 1977: 240) quotes 11,455 millimetres (451.0 in) rain per year, while (Ahrens 2000: 528) quotes 11,680 millimetres (460 in, 12 m) as the average annual rainfall at Mount Waialeale and (Kroll 1995: 188) claims 13,000 millimetres (510 in) falls here. Similarly, The Weather Network and the Guinness Book of Weather Records quote 335 days with rain here while (Simons 1996: 303) suggests that rain falls on an incredible 360 days per year here.
The local tourist industry of Waialeale has promoted it as the wettest spot, although the 38-year average at Mawsynram, Meghalaya, India is higher at 467.4 inches (11,870 mm). Both Mawsynram and Cherrapunji in Meghalaya are recognized by the Guinness Book of World Records as having higher average rainfall. Mawsynram's rainfall is concentrated in the monsoon season, while the rain at Waiʻaleʻale is more evenly distributed through the year.