Rainiest States in America

Hawaii overall is the rainiest state in the US, with a state-wide average of 63.7 inches (1618 millimetres) of rain a year. But few places in Hawaii fit the state's average.

Many weather stations on the islands record less than 20 inches (508 mm) of rainfall a year while others receive well over 100 inches (2540 mm).

Hawaii's climate is dominated by moisture-laden air rolling in off the ocean that releases massive amounts of water on an island's windward side, while the other side enjoys a rain shadow. On the Big Island of Hawaii for instance, Papaikou Mauka near the east coast gets 202 inches (5130 mm) of rain a year. But rainfall drops to just 11 inches (280 mm) annually at Kona Village on the island's western shore.

Mt. Waialeale on Kauai not only gets the most rain in Hawaii, but it's also the rainiest place in the United States. A weather station on the mountain from 1931 to 1960 averaged 460 inches (11,684 millimetres) of rainfall a year.

Other American states with lots of rain year round are in the southeastern part of the country and along the Gulf coast. The top 10 rainiest states average at least 50 inches (1270 mm) of rain a year, or 4 inches (101 mm) a month, based on state-wide averages of monthly precipitation.

During summer, the country's rainiest weather creeps northward into Iowa, West Virginia and New Jersey. While in fall and winter, the northern coastal states of Washington, Massachusetts and Rhode Island join the list of ten rainiest states.

In the wettest months of all, average rainfall amounts to seven inches (178 mm). Only two states normally get that damp every year, Florida during June, July and August, and Hawaii in March and November. While the monthly averages for Hawaii take in wide variation across the state, most places in Florida get similar amounts of rain, close to the state-wide average.