The question of what city in the US receives the most rainfall is complex, as the answer depends entirely on the definition used. Determining the “rainiest” place requires distinguishing between the sheer annual volume of precipitation and the frequency of rainy days. The geographical scope is also important, as extreme weather records in Alaska and Hawaii far surpass those found in the contiguous United States. This complexity often leads to misconceptions, particularly regarding high-profile cities known for frequent, but often light, rainfall.
Defining the Rainiest Location in the US
The absolute national record for annual precipitation volume is held by remote, mountainous locations, not a major city. Mount Waiʻaleʻale on Kauaʻi, Hawaii, is widely recognized as the wettest spot in the country, historically receiving an average of approximately 460 inches of rain per year. This staggering volume places it among the rainiest locations globally, though the monitoring station is no longer fully operational.
For locations with current data, the fishing research station at Little Port Walter on Baranof Island in Alaska holds the record for the highest recent annual precipitation total, averaging about 246 inches. This demonstrates the extreme weather patterns possible outside the lower 48 states. Even the heavily populated Hawaiian city of Hilo records an average of about 130 inches of rain annually, which is significantly higher than any major mainland city.
Meteorological Factors Driving Extreme Precipitation
The extraordinary precipitation totals in places like Mount Waiʻaleʻale are driven by a process known as orographic lift. This occurs when consistent, moisture-laden trade winds are forced upward by steep mountain slopes. As the air gains altitude, it cools, and the water vapor condenses rapidly to form clouds and heavy rainfall on the windward side.
In Alaska, the volume of precipitation at sites like Little Port Walter results from its position along the path of frequent, intense Pacific storm systems. These storms draw significant moisture from the warm ocean and deliver it directly to the coastal mountain ranges. The combination of prevailing westerly winds and the topographical barrier of the Chugach Mountains creates a constant cycle of heavy rain and snowfall.
The Gulf Coast region experiences high annual volumes due to its proximity to the warm Gulf of Mexico waters. This warm, moist air provides the fuel for frequent, intense convective thunderstorms during the summer months. The area is also highly susceptible to tropical systems, where a single storm can drop many inches of rain, significantly boosting the annual total.
Ranking the Rainiest Major Cities in the Lower 48
When focusing on major metropolitan areas within the contiguous United States, the rainiest cities by annual volume are clustered along the Gulf Coast, not the Pacific Northwest. The common perception that cities like Seattle or Portland are the wettest is based on the high number of days with light drizzle, not the total amount of water received. These Pacific cities typically receive less than 40 inches of rain annually.
Cities like Mobile, Alabama, and New Orleans, Louisiana, consistently rank at the top, owing to their exposure to Gulf moisture and severe weather. Mobile often leads the list with an average annual rainfall volume of approximately 67 inches. New Orleans is a close second or third, typically receiving around 64 inches of precipitation each year.
Other cities along the Gulf and Atlantic coasts, such as Fort Lauderdale and Miami, Florida, also feature prominently. This is due to their tropical storm activity and frequent summer downpours, often reporting annual volumes exceeding 60 inches. These high-volume cities are defined by short, heavy bursts of rain.