What U.S. State Gets The Most Rainfall After Hawaii

With lush, tropical landscapes and sandy beaches, Hawaii is an island paradise that also happens to be the rainiest state in the U.S. But what other state comes in second for total average annual rainfall?

If you’re short on time, here’s the quick answer: Louisiana gets the most rainfall of any state after Hawaii, with an average of 60 inches per year across the state.

In this article, we’ll explore annual rainfall averages across the country and look at which states typically see the most and least precipitation each year. We’ll discuss Hawaii’s exceptionally rainy climate, then analyze rainfall patterns across Louisiana to understand why it takes second place for highest state rainfall.

Hawaii Stands Alone With Exceptionally High Rainfall

Hawaii’s Tropical Location Brings Ideal Conditions for Rain

Situated in the central Pacific Ocean, the Hawaiian Islands bask in a tropical climate perfect for frequent and abundant rainfall. Hawaii lies in the path of northeasterly trade winds that pick up moisture as they cross the warm tropical seas.

The islands’ volcanic peaks then force this moist air upward into cooler altitudes, where condensation occurs, resulting in cloud and rainfall formation (National Weather Service). This consistent process leads Hawaii to stand out with exceptionally high annual rainfall totals unmatched elsewhere in the U.S.

Parts of Hawaii See Over 400 Inches of Rain Per Year

While the warm tropical location sets the stage, Hawaii’s dramatic elevation differences account for striking variability in rainfall across the islands. The tallest peaks wring moisture out of trade winds as they ascend, resulting in staggering quantities of rain.

For example, the summit of Mount Waialeale on Kauai sees an eye-popping 460 inches of rainfall per year (Western Regional Climate Center). That’s over 40 feet of rain drenching this peak annually! Other windward mountain areas also tally over 400 inches per year.

Meanwhile, sheltered leeward areas in the islands’ rain shadows may only see around 10-15 inches of rain annually.

Hawaii’s Rainfall Creates Lush Landscapes

This abundant moisture shapes striking contrasts across Hawaii’s landscapes. Lush tropical rainforests cloak the wet windward sides of the islands. These emerald wildernesses harbor rich ecological diversity with countless plant and animal species adapted to the hot and saturated climate.

Waterfalls cascading down cliff faces only add to the dramatic beauty. Just miles away on the arid leeward sides of the islands, desert-like conditions prevail. Hardy cacti and dryland shrubs dot the rocky soils where rainfall rarely reaches.

Overall, Hawaii’s wide rainfall variation occurring over short distances illustrates the powerful influence of climate and topography in shaping the environment of America’s island paradise.

Why Louisiana Gets So Much More Rain Than Most States

With an average annual rainfall of 64 inches, Louisiana gets significantly more precipitation than most other states. Only Hawaii, which gets an astonishing 63 to 460 inches of rain per year depending on location, receives more rainfall on average. Why does the Pelican State get so much more rain?

There are a few key reasons.

Warm, Moist Air From the Gulf of Mexico

Louisiana has access to an abundant source of warm, humid air flowing northward from the Gulf of Mexico. As this air reaches land, it is forced upward by air pressure and geography, allowing water vapor to condense and fall as rain.

This effect is especially enhanced during the summer months when the warm gulf waters produce humid air masses primed to dump heavy rains upon collision with cold fronts sweeping southward across the country.

Frequent Thunderstorms and Showers

The influx of humid, unstable air from the Gulf makes Louisiana prone to frequent thunderstorm development. These storms bring intense but localized downpours. Louisiana averages around 60 thunderstorm days per year.

Scattered showers lacking lightning also dampen the state throughout much of the year.

Warm and cold fronts converging across Louisiana spawn bands of showers and storms. Weather systems tend to stall over the state as well, allowing rain to linger for extended periods. An ample supply of moisture from the Gulf combines with atmospheric dynamics to produce prolonged wet spells.

Effects of the Rainfall: Floods and Bayous

Frequent rainfall has shaped the geography and hydrology of Louisiana. Slow moving rivers and streams swell with runoff, overflowing their banks and carving out the bayous for which Louisiana is known. Flat terrain and soggy soil hinder drainage.

Rivers back up and vast floodplains turn into temporary lakes.

According to National Weather Service records, Louisiana averages around 30 days per year with flooding issues. The Great Flood of 1927 submerged much of south Louisiana under 10 or more feet of water for months, demonstrating the catastrophic flood potential.

Levees and other flood infrastructure aim to mitigate flood risk today, but remain insufficient to contain Louisiana’s rainfall at times.

So in short, Louisiana owes its nation-leading rainfall totals (behind Hawaii) to abundant moisture supplied by the Gulf of Mexico and a geography ripe for squeezing out that moisture in the form of thunderstorms, showers and stalled weather fronts.

Rains shape the bayou landscape and bring a persistent risk of flooding.

Other High-Rainfall States: Florida, Alabama, Mississippi

The Southeast Sees More Rain Than the Northeast

The southeastern states of Florida, Alabama, and Mississippi tend to receive much more annual rainfall than the northeastern states. According to recent data, Florida has an average yearly rainfall of 54 inches, Alabama receives 57 inches of rain per year, and Mississippi sees an average of 55 inches of precipitation annually.

Compare those impressive numbers to a state like New York, which only sees around 46 inches of rain per year.

There are several reasons for this discrepancy. The southeast lies closer to moisture-rich bodies of water like the Gulf of Mexico and the Atlantic Ocean. As humid air masses move inland, the air is forced to rise over land contours like mountains or hills which causes the moisture to condense and fall as rain.

The northeast does not benefit from this abundant moisture to the same degree.

In addition, the southeast is prone to tropical systems that dump incredible amounts of rain over short periods. For example, some areas of Alabama received over 30 inches of rain during Hurricane Danny in 1997!

Tropical weather systems tend to weaken or veer out to sea before impacting most of the northeastern seaboard.

The Rain Shadow Effect Explains West Coast Dryness

The states along the U.S. west coast experience a markedly different precipitation pattern compared to the rainy southeast. Famous for its sunny, temperate climate, California averages just 20 inches of rain per year while Washington and Oregon fare moderately better with 37 and 35 inches respectively.

So what explains the relative aridness of the western states?

The answer lies in the rain shadow effect created by tall mountain ranges that line the Pacific coastline. As moisture-laden air masses approach from over the ocean, the Sierra Nevada and Cascade Mountain Ranges force air to rise over thousands of feet in elevation.

This air cools and condenses, causing water vapor to fall as rain or snow on the windward side. But by the time that air passes over the mountains into states like California, Nevada, and Arizona, much of the original moisture has already rained out.

This leaves the leeward side in a “rain shadow” of dry air.

The rain shadow effect helps shed light on precipitation patterns across the U.S. and demonstrates why states like Washington and Florida can differ so drastically in yearly rainfall totals despite bordering major bodies of water.

The Driest States in the Continental U.S.

The states in the continental U.S. with the least annual rainfall include Arizona and Nevada, areas with vast deserts and little precipitation much of the year. Yet even in these arid regions, innovative water management strategies allow communities to bloom and thrive despite the dry conditions.

Desert States Top the List for Lowest Rainfall

According to the U.S. Drought Monitor^[1], Arizona and Nevada consistently rank as the driest states in the U.S., with average annual rainfall of around 13 inches and 10 inches respectively. Parts of these states are covered by the Mojave, Sonoran and Chihuahuan deserts, areas that can go years with little rainfall.

Parts of Arizona and California See Little Rain

Within Arizona and California, Yuma and Death Valley stand out as particularly arid. Yuma averages a meager 3.2 inches of rain per year^[2], while Death Valley receives 1.5 inches on average^[3]. Water is scarce in these environments, yet resilient plants and wildlife have adapted to thrive.

Adapting Infrastructure to Thrive in Arid Climates

Communities in the driest states require creative water management strategies. Water is piped in or pumped from underground aquifers. Dams and reservoirs bank as much water as possible from rare rainfall events.

And increasing emphasis is placed on water conservation, from low-flow fixtures to drought-tolerant landscaping.

The desert Southwest may be sunny and dry, but smart resource management allows cities like Phoenix, Las Vegas and Palm Springs to bloom even in the arid landscapes.

Conclusion

While sunny weather prevails in much of the United States, a few states—particularly Hawaii and the Gulf region—see epic annual rainfall thanks to tropical climates and humidity. Understanding patterns of rainfall distribution allows communities to plan infrastructure with their climate in mind—whether that means managing floods in Louisiana or conserving water in Arizona.

Next time you visit Hawaii during one of the state’s 265 rainy days per year, appreciate that you’re witnessing the peak of U.S. rainfall. But meanwhile, the residents of Louisiana don’t need to travel far to experience their own exceptional version of a damp climate!

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