When Exactly Is The Rainy Season In Hawaii?

With its usually sunny weather and famous rainbows, Hawaii seems like an endless summer paradise. But the islands do actually have a distinct rainy season. If you’re planning a trip to Hawaii, you may be wondering exactly when you can expect more rainfall.

If you’re short on time, here’s a quick answer to your question: The rainy season in Hawaii runs from November through March, with the wettest months typically being December and January.

In this comprehensive guide, we will cover everything you need to know about Hawaii’s rainy season, including the key details on timing, how much rain to expect, impacts on travel, and tips for visiting during the wet months.

What are the Start and End Dates of Hawaii’s Rainy Season?

The rainy season in Hawaii is a bit tricky to pin down, as the weather here varies quite a bit from island to island. However, there are some general patterns that help define the wetter months across the Hawaiian Islands.

Oahu and Maui’s Rainy Season

On Oahu and Maui, the rainy season typically runs from November through March. The winter months bring more storms and rainfall to Hawaii’s most visited islands.

According to weather records, Oahu receives an average of almost 15 inches of rain just in the month of December alone.

March wraps up the wet weather, with lower rainfall totals as spring approaches.

Kauai’s Rainy Season

On verdant Kauai island, the rain can fall more frequently. While it rains year-round here, Kauai sees its heaviest rainfall from November through April. The island’s lush landscape relies on about 50 inches of rainfall on average during these wet winter months.

The Big Island’s Rainy Season

Due to its size and highly varied terrain, the Big Island has more unpredictable rainy seasons. However, the winter tends to be the wetter time of year here as well. From November through April, rainfall averages range from about 15 inches on the drier western side to over 30 inches on the tropical and mountainous east side.

The other key factor is that Hawaii’s rainy season often coincides with the cooler winter months when Pacific storms track farther south. So not only does the rain pick up, but temperatures drop a few degrees as well during this “winter.”

Rain All Year in Hawaii

It’s important to note that Hawaii truly sees rainfall throughout the year. Even during the summer/drier months of May through October, brief passing showers and occasional storms can develop impacting all islands.

Thanks to Hawaii’s moderate tropical temperatures warming the Pacific waters, the potential for pop up downpours remains year-round.

So while timing your trip to avoid the “rainy season” is a good plan, you’ll still want to pack a travel umbrella or light rain jacket regardless of the month! The phrase “lucky you live Hawaii” certainly applies to the state’s incredibly beautiful but unpredictable weather 

How Much Rain Falls During Hawaii’s Wet Season?

Hawaii’s rainy season, known locally as the wet season or winter season, sees significantly more rainfall than the dry summer months. During this wetter part of the year from October through April, the islands experience more rainfall, larger surf, and occasional storms.

According to rainfall data from the National Weather Service, Hawaii’s wettest area is on the northeast side of Mount Waiʻaleʻale on Kauai, which sees an incredible average annual rainfall of 460 inches (nearly 40 feet!).

Other parts of the Hawaiian Islands see less extreme but still significant rainfall during this wet period:

• Honolulu averages just under 16 inches of rain during wet season months
• Hilo on the Big Island averages over 128 inches of rainfall from October to April
• Kahului, Maui sees about 27 inches of rain during these months
• Lihue, Kauai averages nearly 35 inches of precipitation in the wet season

The contrast between Hawaii’s dry and wet seasons is striking. While rain is always a possibility on the tropical islands, the wetter months see 4-5 times more rainfall than the summer dry season.

Hawaii’s wet season corresponds with the cooler winter months when North Pacific storms track farther south, bringing more clouds, rain showers, and potential flooding. The winter months also have larger surf, especially on north-facing shores.

While less ideal for beach days, the lush green mountainsides and cascading waterfalls following Hawaii’s rainy season have their own beauty.

So during your Hawaii vacation, be prepared with rain jackets and umbrellas if you’re visiting between October and April. Check forecasts regularly as rainfall can vary significantly in different areas on any given day.

But don’t let a few passing showers stop you from enjoying Hawaii’s natural wonders during this cooler, wetter part of the year.

Also read: How Much Rain Does Hawaii Get Per Year?

What Causes Hawaii’s Annual Rainy Season?

Hawaii’s rainy season, which typically occurs between October and April each year, is caused by several interacting weather factors. Here’s an overview of what leads to this annual period of heavy rainfall:

Shift in Wind Patterns

In the summer, steady northeasterly trade winds prevail across the islands. However, in the fall, high pressure systems to the north begin weakening, allowing the trade winds to shift to more variable southerly and westerly winds.

These winds carry more moisture and instability, making rainfall more likely.

Increase in Storminess

The change in winds coincides with an uptick in storminess, both locally and out over the eastern Pacific Ocean. Low pressure systems that form near Hawaii, called Kona storms, often tap into tropical moisture and dump heavy rainfall.

Meanwhile, cold fronts and upper level disturbances moving in from the west/northwest become more frequent as well.

Warmer Ocean Temperatures

Sea surface temperatures surrounding Hawaii reach their annual peak from August through October. This supplies extra heat and moisture to fuel enhanced shower and thunderstorm development, especially when combined with instability from cool upper level troughs swinging down across the islands during fall and winter.

In short, the culmination of shifting winds, increasing storminess, and warm ocean waters all join forces to make Hawaii’s rainy season a time of significant rainfall and isolated flooding each year. Showers tend to focus over windward areas but also affect leeward zones at times.

What is the Weather Like in Hawaii During the Rainy Months?

The rainy season in Hawaii typically runs from November through March. During these months, the islands experience more rainfall, higher humidity, and slightly cooler temperatures than the rest of the year.

However, “rainy season” in Hawaii is a bit of a misnomer – it’s rarely pouring rain all day long. Instead, expect brief but heavy showers that come and go quickly throughout the day.

Increased Rainfall

The increased rainfall during Hawaii’s winter months is caused by storms and cold fronts that sweep down from the north Pacific. The average rainfall ranges from 5-15 inches per month on the leeward (drier) sides of the islands to 15-25 inches per month on windward (wetter) sides.

The most rain falls at higher elevations.

While rain showers can happen anytime, they tend to be more frequent in the afternoon and evening. Mornings typically start out sunny or partly cloudy before clouds build and rains come later in the day. Showers often blow through very quickly thanks to brisk trade winds.

Higher Humidity

With more rainfall comes higher humidity levels. The relative humidity during Hawaii’s rainy season averages 70-80%, compared to 60-70% during the warmer months. This can make the cooler temps feel extra chilly!

The good news is the rain helps keep everything lush and green across the islands during winter. And when the rains pause, the humidity gives way to rainbows!

Slightly Cooler Temps

While Hawaii is known for warm weather year-round, temperatures do dip a few degrees during the rainy season. Average highs are typically in the upper 70s (Fahrenheit) at lower elevations to low 70s at higher elevations. Overnight lows range from the mid 60s to low 60s.

Compared to summer highs in the mid 80s, it may feel downright chilly when the winds and rains pick up! Be sure to pack layers and a lightweight rain jacket if visiting during the winter.

A few times a year during the rainy season, cold storms from Alaska can bring heavy rain, thunderstorms, and uncharacteristically cold weather. But after a day or two of raw weather, temperatures rebound back to normal mild conditions.

Also read: What To Wear In Hawaii: The Complete Packing Guide

How Does the Rainy Season Impact Travel to Hawaii?

The rainy season in Hawaii, which typically runs from October through April, can have some impacts on travel to the islands. However, with proper planning and flexibility, visitors can still have an amazing time.

Potential Travel Disruptions

During the wetter months, Hawaii may experience heavy downpours, thunderstorms, flash flooding, and high winds. This can occasionally cause the following travel issues:

• Flight delays or cancellations at airports
• Temporary road closures due to mudslides, flooding, or debris
• Power outages at hotels or vacation rentals
• Some attraction closures, especially hiking trails with hazardous conditions

That said, major disruptions more commonly occur during severe storm systems and are often fairly localized. So with flexible planning, travelers can work around them.

Tips for Visiting Hawaii in Rainy Season

With the right mindset and preparation, Hawaii’s rainy season can be a wonderful time for a vacation. Some tips include:

• Pack water-resistant shoes and bring lightweight rain gear.
• Have backup indoor activities planned each day in case of rain.
• Consider staying at resorts in drier areas like Waikiki or the Kohala Coast on the Big Island.
• Rent a Jeep or SUV vehicle to handle wet roads, especially on more rural islands.
• Purchase travel insurance for trip delay or cancellation protection.

The rain often comes in short bursts, allowing time for other adventures between showers. And the lush green mountainsides and waterfalls can be incredible to see after a rainstorm passes.

Great Activities in Rainy Season

There are also some special activities that shine during Hawaii’s wet season, like:

• Whale watching – Humpback whales migrate to Hawaii from December through April.
• Indoor attractions like the Bishop Museum in Honolulu or Maui Mall.
• Relaxing at spas and resort pools between rain bursts.
• Cooking classes featuring local cuisine.
• Rainy day cultural activities like hula shows, ukulele lessons, or lei making.

In the end, Hawaii’s gorgeous beaches, lush jungles, and aloha spirit shine through regardless of the weather. With flexibility and preparation, visitors in rainy season can discover all the magic the islands have to offer.

Also read: Does It Rain A Lot In Hawaii?

Tips for Visiting Hawaii During the Rainy Season

The rainy season in Hawaii generally runs from November through March, with the wettest months typically being December and January. While rain showers are more frequent during this time, there are still plenty of sunny days mixed in.

With some preparation and flexibility, you can still have an amazing trip to Hawaii amidst the rainy season.

Pack Properly

Be sure to pack lightly breathable clothing, as well as waterproof shoes and jackets, which will keep you comfortable in Hawaii’s tropical climate.

Bringing a compact umbrella and water-resistant bag for your camera or other essentials is also wise. Packing a poncho gives you stylish coverage too.

Also read: What To Pack For Your Hawaii Vacation: The Ultimate Packing List

Have Back-Up Indoor Activities

While Hawaii’s scenic beaches and trails are gorgeous, rainy days happen. Having some indoor activities planned like museum visits, lū‘au shows, or shopping excursions means you’ll still have fun no matter the weather.

The Bishop Museum and ‘Iolani Palace in Honolulu or the Maui Ocean Center are fascinating rainy day options.

Be Flexible

Hawaii’s microclimates means that it could be raining on one side of an island but sunny just a 10-15 minute drive away. Having some flexibility to shift plans based on weather can make a big difference in enjoying sun or avoiding showers.

Apps like Hawaii Radar make it easy to monitor rain bands in real-time.

Enjoy the Rain

While not ideal for beaches and hiking, Hawaii’s rain showers can also be quite beautiful, especially on lush tropical terrain. Listen to the soothing sound of rain drumming on palm fronds or watch waterfalls gush with rain-fed energy. It’s a uniquely Hawaiian experience!

A little preparation means visiting Hawaii during rainy season can still be fantastic. Just go with an open mindset to enjoy both sunny and rainy moments!

Also read: What To Do In Hawaii When It Rains

Conclusion

As you can see, while Hawaii does have wetter months, the rainy season doesn’t have to deter you from visiting. With proper planning and preparation, you can still have an amazing time in Hawaii between November and March.

The rainfall brings lush vegetation, fewer crowds, and great deals on hotels and flights during this low tourism season. Just make sure to pack wisely and remain flexible with outdoor activities. With stunning scenery and world-class beaches year-round, Hawaii offers plenty to enjoy rain or shine!

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