Trip Planning

Big Island Weather by Month: A Guide for Your Hawaiʻi Trip

Wondering about the weather for your trip to Hawaiʻi? The Big Island's forecast is a tale of two sides and many microclimates, changing month by month.

July 20, 2026 • 9 min read • by Big Island Tours Editorial

Planning a trip to the Big Island of Hawaiʻi brings visions of sun-drenched beaches and swaying palms. While you'll certainly find that, the island's weather is far more complex and fascinating. Home to 8 of the world’s 13 climate zones, your experience can change dramatically just by driving an hour. Understanding the island's seasons and microclimates month by month is the key to a perfectly planned vacation.

This guide breaks down the typical weather patterns across the Big Island, from the sunny shores of Kailua-Kona to the lush landscapes of Hilo and the chilly summits of the great volcanoes. We'll help you know what to expect and how to pack, ensuring you're prepared for anything the island has to offer.

Understanding Hawaiʻi's Two Seasons

Unlike the four distinct seasons of the mainland, Hawaiʻi primarily has two: kau, the warmer, drier summer season, and hoʻoilo, the cooler, rainier winter season.

Kau (Summer): Typically runs from May to October. This season sees higher temperatures, more consistent sunshine (especially on the leeward side), and generally calmer ocean conditions. It's also technically hurricane season, though direct hits are historically rare.
Hoʻoilo (Winter): Lasts from November to April. Temperatures are slightly cooler, and this is when the islands receive the majority of their annual rainfall. This is particularly true for the windward (east) sides. Winter also brings large ocean swells, creating the iconic big waves on north-facing shores.

While air temperatures only fluctuate about 8-10°F between seasons at sea level, the changes in rainfall and ocean conditions are significant.

The Power of Big Island Microclimates

Nowhere is the concept of microclimates more pronounced than on the Big Island. The massive volcanoes of Mauna Kea and Mauna Loa block the prevailing trade winds, creating a stark difference between the windward (east) and leeward (west) sides.

Leeward Side (Kona & Kohala Coast): This is the dry, sunny side of the island. Areas like Kailua-Kona, Waikoloa, and the Kohala Coast receive very little rainfall year-round. You can almost guarantee sunshine here any day of the year. This is where you'll find most of the island's resorts and famous beaches.
Windward Side (Hilo & Hāmākua Coast): This side faces the moisture-laden trade winds, making it lush, green, and wet. Hilo is one of the rainiest cities in the United States. Don't let that deter you; the rain often comes in short, passing showers that keep the rainforests and waterfalls flowing beautifully. Rain is simply a part of the Hilo experience.
Kaʻū District (South): This southern region is arid and windswept, home to deserts and dramatic, raw landscapes. It has its own unique, often dry, weather patterns.
Saddle Road & Volcanoes: The interior of the island and the high-altitude summits are another world entirely. Temperatures at Hawaiʻi Volcanoes National Park (around 4,000 ft elevation) are often 15-20°F cooler than at the coast. The summits of Mauna Kea and Mauna Loa (nearly 14,000 ft) get cold enough to see snow in the winter.

Because of this diversity, you can often escape the rain on one side of the island by simply driving to the other.

Big Island Weather: A Month-by-Month Breakdown

Here’s a general look at what you can expect throughout the year. Temperatures listed are general sea-level averages, with Kona typically being warmer and drier, and Hilo being slightly cooler and much wetter.

Winter: December, January & February

This is the heart of the hoʻoilo (wet) season. It's also peak season for whale watching, as humpback whales migrate to Hawaiian waters.

Temperatures: Average daytime highs are 79-82°F (26-28°C).
Precipitation: This is the rainiest time of year for Hilo and the windward side. Passing showers are frequent. The Kona side remains largely dry, though occasional fronts can bring a day or two of island-wide rain.
Ocean Conditions: Large swells are common on north-facing shores. This is great for expert surfers but can create dangerous conditions for swimming at beaches like Hāpuna. South-facing shores are typically calm.
Highlights: Incredible whale watching. Snow often dusts the top of Mauna Kea. Waterfalls are at their most powerful. It's a great time for exploring the dramatic, stormy coastlines.

Spring: March, April & May

Spring is a beautiful shoulder season. The winter rains begin to subside, and the island is incredibly green and vibrant. The visitor crowds from winter also begin to thin out.

Temperatures: Average daytime highs climb to 80-84°F (27-29°C).
Precipitation: March can still be quite wet on the windward side, but rainfall lessens significantly through April and May. The leeward side remains sunny as always.
Ocean Conditions: The large winter swells begin to fade, and ocean conditions generally become calmer and more predictable, making it a great time for snorkeling and diving all around the island.
Highlights: A fantastic time for hiking as trails are less muddy than in winter but the landscape is still lush. Fewer crowds make it a relaxing time to visit. This is an ideal period for an all-around trip with pleasant weather nearly everywhere.

Summer: June, July & August

Welcome to kau (dry) season. This is the warmest and driest time of year for most of the island and the peak season for family travel.

Temperatures: Average daytime highs are 85-87°F (29-31°C). It can feel quite humid.
Precipitation: This is the driest time of year for the entire island. Even Hilo sees a reduction in its daily rainfall. The exception is the Kona district, which can see afternoon showers in its unique "rainy" season, though these are typically brief.
Ocean Conditions: The ocean is generally at its calmest, especially on north and east shores. This is the best time of year for snorkeling in places that are too rough in winter. This is a topic our experts at Big Island Tours love to discuss.
Highlights: Perfect beach weather. Ideal for water activities like snorkeling, paddleboarding, and kayaking. Long, sunny days provide ample time for exploration.

Fall: September, October & November

Fall is another wonderful shoulder season. The summer heat lingers, but the crowds depart. It's considered by many locals to be one of the best times of the year.

Temperatures: Average daytime highs stay warm, around 84-86°F (29-30°C).
Precipitation: September is often still very dry. Rain begins to creep back into the forecast in October, and by November, the transition to the wet season is well underway on the windward side.
Ocean Conditions: The ocean remains calm through September and into October. Winter swells may begin to show up on north-facing shores in late October or November.
Highlights: The Ironman World Championship takes place in Kailua-Kona in October. The weather is still excellent for beach days, but with a more local, laid-back feel. Great deals on flights and accommodation can often be found.

A Note on Hurricane Season

Hurricane season in the Central Pacific officially runs from June 1 through November 30. It's important to be aware of this, but not to let it dominate your planning. According to the National Weather Service, Hawaiʻi is a small target in a very large ocean, and direct hits from hurricanes are very rare. The islands are more often affected by tropical storms or depressions that bring a few days of gusty winds and heavy rain.

If you are traveling during this time, simply stay informed. Monitor alerts from the Central Pacific Hurricane Center and have a flexible itinerary in the unlikely event a storm system approaches.

Packing for the Big Island's Weather

The key to packing for the Big Island is layers.

Sun Essentials: High SPF reef-safe sunscreen, sunglasses, and a wide-brimmed hat.
Light Layers: Lightweight shirts, shorts, and dresses for the coastal areas.
Rain Gear: A lightweight, packable rain jacket is a must, no matter the season. You'll be glad you have it in Hilo or at elevation.
Warm Layers: A fleece, sweater, or warm jacket, plus long pants, are essential if you plan to visit Hawaiʻi Volcanoes National Park or go stargazing on Mauna Kea. Temperatures can drop into the 30s and 40s (°F) at the visitor center.
Footwear: Bring sandals/slippers (slippahs), but also a pair of sturdy, closed-toe walking shoes or hiking boots for trails and lava fields.

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Frequently asked questions

What is the best month to visit the Big Island for good weather?

For the best balance of sunshine, pleasant temperatures, and calm oceans, the shoulder months of April, May, September, and October are often considered ideal. You'll miss the winter rains and the peak summer crowds.

What is the rainiest month on the Big Island?

The months from December to March are typically the rainiest, especially on the windward (Hilo) side of the island. However, the leeward (Kona) side remains relatively dry even during these months.

Is the weather in Kona and Hilo really that different?

Yes, it's a dramatic difference. Kona and the Kohala Coast are very dry and sunny year-round. Hilo, on the windward side, is a lush rainforest environment that receives significant rainfall throughout the year, keeping its waterfalls and gardens vibrant.

When is hurricane season in Hawaiʻi?

Hurricane season runs from June 1 to November 30. While visitors should be aware, direct hits on the Hawaiian Islands are historically rare. It's more common to experience the remnants of a tropical storm, which may bring a few days of rain and wind.

Does it ever get cold on the Big Island?

Yes, at higher elevations. While coastal areas are warm year-round, temperatures at Hawaiʻi Volcanoes National Park (4,000 ft) can be cool. The summits of Mauna Kea and Mauna Loa (nearly 14,000 ft) are very cold and receive snow in the winter.

Can you swim in the ocean during the winter on the Big Island?

Absolutely. While north-facing shores experience large, powerful surf, the south and west-facing shores (like those in Kona) are generally calm and perfect for swimming and snorkeling year-round. Always check ocean conditions before entering the water.

When is whale watching season on the Big Island?

The peak season for spotting migrating humpback whales is from December through March. The Kohala Coast on the leeward side is one of the best places in Hawaiʻi for whale watching from shore or on a boat tour.