May is when the Big Island of Hawai'i pivots from wet season to dry, and you feel it first on the leeward Kona coast. The North Pacific swells that churn the shoreline from November through March have largely faded, trade winds return with a steadiness that keeps the air comfortable, and the western beaches settle into a calm that makes reliable snorkeling possible from shore. The island-wide temperature averages look deceptively cool because this place rises from sea level to the sub-alpine summit of Mauna Kea. Down along Ali'i Drive in Kailua-Kona or at the Kohala Coast resorts, afternoons run closer to 28-30°C (82-86°F). Up in Volcano village, you might want a fleece by 7:00 PM.
The timing has practical advantages. Mainland schools stay in session through most of the month, so the summer family wave hasn't landed. Hotel rates sit near the island's annual average, well below the December-through-March window. Lei Day brings lei-making competitions and hula performances to venues across Hilo at the start of the month, and the early mango harvest begins appearing at the Hilo Farmers Market by mid-May.
Mind you, May has trade-offs. The windward Hilo coast stays damp regardless of season, and vog from Kīlauea can settle over the south and west on still days. Humpback whale season wrapped up in April, so if cetaceans were the draw, you've missed it. But for a month that threads the needle between improving weather, moderate pricing, and genuinely thin crowds, May tends to deliver.
Why visit in May
- The dry season begins on the Kona Coast, and ocean conditions shift toward calmer, clearer water as the North Pacific swell season ends. Shore snorkeling and kayaking along the western side become consistently viable.
- Crowds are noticeably thinner than both the winter peak and the summer rush. You can often walk into popular Kailua-Kona restaurants without a reservation.
- Waterfalls along the Hamakua Coast and in Waipi'o Valley still run at full force from winter rains, while the trails leading to them have dried enough for comfortable hiking.
- Ideal conditions for exploring Hawai'i Volcanoes National Park. Paths like the Kīlauea Iki loop are drying out but haven't baked in summer heat.
Worth knowing
- Humpback whale season ends in April. Tour operators still run boats, but sighting odds drop sharply after the first week of May.
- Vog (volcanic haze from Kīlauea) can drift over Kailua-Kona and the South Kona coast on low-wind days, reducing air quality and dulling sunset colors.
- The Hilo and Hamakua coasts receive rain year-round. Expect at least 3-4 wet days per week on the eastern side regardless of the island-wide average.
Best for
Think twice if
May sits at the hinge between wet and dry seasons. The Kona side typically turns a corner, with trade winds returning more consistently and afternoon showers becoming shorter and less frequent. The island-wide average high of 15.6°C (60°F) and low of 7.1°C (45°F) reflect the enormous elevation range, from humid sea-level coasts to the sub-alpine summit zone above 4,000 meters. At beach level along the western coast, the gap between these averages and what you feel is dramatic. Humidity sits at 75%, which feels comfortable with the trades blowing but sticky on still Hilo afternoons. Expect roughly 77mm of rain spread across 11 days, most of it falling on the windward side and at higher elevations.
Seasonal caution
- Vog (volcanic smog) from Kīlauea can cause respiratory discomfort on the leeward coast during periods of weak trade winds. Check the Hawai'i Interagency Vog Information Dashboard before planning outdoor activities on the south and west sides.
- Mauna Kea summit temperatures drop below 0°C (32°F) after sunset year-round. Altitude sickness is a real risk at 4,200 meters (13,796 feet). The Visitor Information Station at 2,800 meters (9,200 feet) recommends acclimatizing for at least 30 minutes before driving higher.
Year-round climate
Averages from the last 5 years.
| Month | Avg high (°C) | Avg low (°C) | Rainfall (mm) |
|---|---|---|---|
| Jan | 15 | 6 | 72 |
| Feb | 14 | 5 | 85 |
| Mar | 14 | 6 | 111 |
| Apr | 15 | 6 | 91 |
| May | 16 | 7 | 77 |
| Jun | 17 | 8 | 25 |
| Jul | 18 | 8 | 54 |
| Aug | 18 | 8 | 87 |
| Sep | 18 | 8 | 53 |
| Oct | 17 | 8 | 76 |
| Nov | 16 | 7 | 86 |
| Dec | 15 | 7 | 65 |
Holidays and festivals in May
Public holidays
- Truman Day(Truman Day)8 May 2027
- Memorial Day(Memorial Day)31 May 2027
Best things to do in May
Snorkel Kealakekua Bay
water sportsThe Captain Cook monument marks one of the best reef systems in the state. A 1.8-mile (2.9 km) trail drops about 400 meters (1,300 feet) to the bay, or you can kayak across from Nāpō'opo'o. Spinner dolphins frequent the bay in the early morning, and coral coverage here is denser than at most Kohala Coast sites.
Ocean swells drop as the North Pacific storm season ends, and water clarity on the Kona coast often exceeds 25 meters (80 feet) in May. Fewer tour boats than summer means less surface churn.Booking tipKayak rental permits for the bay are limited. Reserve through a licensed outfitter at least a week ahead, especially for weekend slots.
Hike the Kīlauea Iki Trail
hikingA 6.4 km (4-mile) loop that drops into a crater formed by a 1959 eruption. You cross the solidified lava lake floor, still warm enough to steam where rainwater seeps through cracks. The smell of sulfur drifts in patches. The trail passes through native 'ōhi'a lehua forest on the rim before descending.
Trails are drying from the wet season, and cooler temperatures at the 1,200-meter (3,900-foot) elevation keep midday hiking comfortable. By July and August, the crater floor radiates stored heat that makes the crossing genuinely unpleasant.Booking tipNo reservation needed, but arrive before 9:00 AM to get parking at the trailhead lot inside the national park.
Night manta ray snorkel off Keauhou Bay
wildlifeReef manta rays, some with wingspans over 3.5 meters (12 feet), feed on plankton attracted by dive lights. You float at the surface with a lighted board while the mantas glide beneath you, sometimes close enough to feel the push of water from a wing stroke. The scale of these animals is hard to process until one passes directly below.
Calmer nearshore conditions mean fewer cancellations than during the winter swell season. Plankton blooms from the spring nutrient cycle tend to draw more mantas closer to shore.Booking tipOperators typically run 2 departures per night. The second departure (around 8:30 PM) tends to have fewer snorkelers per boat.
Stargazing from Mauna Kea
natureThe Visitor Information Station offers free nightly stargazing programs with telescopes. On clear nights, the Milky Way core becomes visible after 9:00 PM, and the absence of light pollution at this altitude is stark. The sky looks physically different from what you see at sea level.
May marks the transition to drier upper-atmosphere conditions, with cloud cover at the summit dropping compared to winter. The galactic core rises earlier in the evening each night through late spring.Booking tipDrive up before sunset to acclimatize. The road to the summit requires a 4WD vehicle, though the station is accessible by any car.
Explore Waipi'o Valley
sightseeingA steep, narrow road drops 300 meters (900 feet) into a valley that once held the political seat of Hawaiian royalty. Taro fields line the valley floor, a black-sand beach runs along the coast, and Hi'ilawe Falls drops 442 meters (1,450 feet) from the back wall. The sound of the surf echoes off the valley walls in a way that makes the scale legible.
Waterfalls are still running strong from the wet season, but the valley floor is drier and more walkable than in March or April. By September, the smaller falls thin to a trickle.Booking tipThe access road has a 25% grade in places. Walk down or take a guided shuttle. Do not attempt it in a standard rental car.
Visit Pu'uhonua o Hōnaunau National Historical Park
cultureA restored Hawaiian temple complex and place of refuge on the South Kona coast. The Great Wall, built around 1550, still stands over 3 meters (10 feet) high. Carved ki'i akua (wooden temple images) line the grounds near the reconstructed Hale o Keawe temple. The adjacent Two Step lava shelf is a popular shore-snorkel entry, named for the 2 natural steps down into the water.
Pleasant coastal temperatures and calmer water make it comfortable to combine the cultural site with a snorkeling session at Two Step. In winter months, large swells make the snorkeling entry dangerous.Drive the Hamakua Coast to Akaka Falls
scenic driveThe 80 km (50-mile) stretch of Highway 19 between Hilo and Waimea runs along sea cliffs thick with tropical vegetation. At Akaka Falls State Park, the water drops 135 meters (442 feet) into a gorge lined with bamboo and wild ginger. The air smells of damp earth and plumeria along the loop trail. The Pepe'ekeo scenic route offers a slower, older road segment under monkeypod canopy.
The coast is at peak lushness after winter rains, and waterfalls along the route are full. By late summer, some of the smaller cascades dry up entirely.What to eat in May
In season: fruit
White Pirie mango
The Big Island's signature mango variety ripens in mid-May. Smaller and more fibrous than mainland grocery-store mangoes, with an intense floral sweetness that hits before you even cut the skin. Roadside stands in South Kona and Captain Cook sell them by the bag.
Lilikoi (passion fruit)
Grows wild across the Hamakua Coast and into the Volcano area. May marks the start of peak fruiting. The tart, almost aggressively fragrant pulp shows up in butter, chiffon pie, and fresh juice at Hilo bakeries and cafes.
On menus now
Poke with fresh-caught ahi
Yellowfin tuna runs strong through spring. Suisan Fish Market in Hilo sells poke by the pound, seasoned with limu (seaweed), kukui nut, and sea salt. The May catch tends to be clean-tasting, pulled from water that hasn't warmed to summer temperatures yet.
Street food peaks
Shave ice with local fruit syrups
Year-round treat, but May is when the first syrups made from freshly picked local fruit replace the concentrates. The texture and flavor difference is real, especially with lilikoi or mango topping over finely shaved ice.
In markets
Breadfruit ('ulu)
Coming into season from May through fall. Traditionally steamed or roasted in an imu (underground oven), 'ulu has a starchy, potato-like texture that turns creamy when cooked. You'll find it as a side dish or occasionally prepared as fries at Kona-side restaurants.
Regular events in May
Lei Day CelebrationsFree
Hawai'i's statewide celebration of the lei, observed every year since 1928. On the Big Island, Hilo typically hosts lei-making competitions, hula performances, and craft exhibitions. Schools and community centers across the island hold their own events. The atmosphere is relaxed and genuinely community-driven.
May 1Kodomo no Hi (Children's Day)Free
A Japanese cultural tradition widely observed in Hawai'i, where families fly koinobori (carp-shaped wind streamers) from poles and rooftops. The Big Island's Japanese-American community, particularly in Hilo and Waimea, marks the day with colorful displays. Look for the streamers flying above homes in the neighborhoods along the Wailuku River.
May 5Memorial Day CeremoniesFree
Observances take place at veterans' cemeteries and memorials across the island, with the largest gathering typically held at the Hawai'i Island Veterans Cemetery in Hilo. The 3-day weekend draws local families to the beaches, particularly Hapuna and the Kohala Coast parks.
Last Monday of MayBest places this May
Hawai'i Volcanoes National Park
national parkThe drier May conditions make the park's 240 km (150 miles) of trails more accessible than during the wettest months. The Devastation Trail offers an easy 1.6 km (1-mile) walk through a cinder field. Steam vents along Crater Rim Drive are always active. Check the ranger station for current volcanic activity, as lava surface flows follow no seasonal schedule.
VolcanoAkaka Falls State Park
state parkA short 0.6 km (0.4-mile) paved loop leads to overlooks of both Kahuna Falls and the main cascade. The surrounding rainforest drips with wild orchids, and you can hear the falls well before you see them. The waterfall runs strongest from January through May, fed by the wet season on this part of the coast.
HonomuHapuna Beach State Recreation Area
beachAn 800-meter (0.5-mile) crescent of white sand on the Kohala Coast. Surf calms considerably in May compared to winter months. The water is warm enough to swim without a wetsuit, and the beach park has full facilities. Arrive before 10:00 AM on weekends for guaranteed parking.
Kohala CoastHilo Farmers Market
marketThe full market runs Wednesday and Saturday, with over 200 vendors on Saturdays. May brings the first local mangoes alongside rambutan, starfruit, and Kona-grown avocados. Prepared food stalls sell malasadas and fresh coconut water. Opens at 6:00 AM, and the best produce goes within the first 2 hours.
HiloPapakōlea Green Sand Beach
beachOne of only 4 green sand beaches in the world, colored by olivine crystals from the eroded Pu'u Mahana cinder cone at Ka Lae (South Point), the southernmost point in the United States. Reaching it requires a 5 km (3-mile) round-trip hike from the parking area across an exposed, treeless landscape. May's moderate temperatures make the walk more bearable than midsummer.
Ka'uPu'uhonua o Hōnaunau National Historical Park
national historical parkMorning is the time. Arrive before 10:00 AM to walk the walled temple compound in relative solitude, then cross to the south side of the park boundary for shore snorkeling. The carved wooden figures and the ocean setting are worth at least 2 hours, separate from any time in the water.
South Kona
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Insider tips
Stay in Hilo for at least 2 nights instead of basing entirely in Kona. Hotels in Hilo typically run significantly cheaper than equivalent Kohala Coast properties, and you'll be closer to the national park, Akaka Falls, and the Waipi'o Valley overlook. The drive between the two coasts takes about 90 minutes on Saddle Road (Highway 200).
Vog clears on days with strong trade winds from the northeast. Check the wind forecast before committing to a Kona-side beach day. If the trades have stalled, the Hilo side often has cleaner air since the volcanic emissions drift southwest.
The Wednesday session at the Hilo Farmers Market carries most of the same produce as Saturday's but with a fraction of the crowd. Arrive by 7:00 AM for first pick without competing for parking.
If you're entering the water at Two Step near Pu'uhonua o Hōnaunau, look for the flat lava shelf on the south side of the park boundary. Most first-timers walk past it searching for a sandy beach that doesn't exist.
Fill your gas tank every time you pass through Waimea or Kailua-Kona. Stations on the Ka'u coast and in Volcano are sparse, and running low on the remote south side is a real problem, not a minor inconvenience.
Avoid these mistakes
- Booking a whale-watching tour in May. Operators will happily take bookings, but humpback whales have largely left Hawaiian waters by late April. The manta ray night snorkel off Keauhou is a better use of the same budget.
- Underestimating Big Island driving distances. The island is 150 km (93 miles) across. A day trip from the Kohala Coast to Hawai'i Volcanoes National Park is a 4-hour round trip, and the return on Saddle Road in the dark demands real concentration.
- Packing only beach clothes. The temperature swing between the coast and the upper elevations catches visitors off guard weekly. At least one proper warm layer per person prevents a miserable stargazing session or a cold evening in Volcano village.
- Skipping the Hilo side because the forecast shows rain. The eastern coast gets brief showers that pass quickly, and between them the waterfalls, rainforest, and the farmers market are at their best. A full-day downpour is uncommon even in May.
Practical tips for May
Book rental cars early for Memorial Day weekend. The Big Island has fewer rental options than O'ahu, and the holiday weekend can clean out Kona and Hilo airport inventory. A 4WD vehicle is recommended only if you plan to drive above the Mauna Kea Visitor Information Station. Standard cars handle the rest of the island's paved roads. The national park entrance fee covers 7 days, so consider splitting your Volcanoes visit across 2 separate days. Most Kona-side restaurants keep normal hours through May, but a handful of seasonal spots between Kailua-Kona and Captain Cook close for maintenance in the shoulder season. Verify before driving 45 minutes south for dinner. The Big Island scores 7.8 out of 10 for family friendliness (see /research/family-friendliness/), and children under 15 enter the national park free.
FAQ
Is May a good time to visit Big Island?
May is a strong shoulder-season month, ranking around 5th out of 12. You get the start of the dry season on the Kona coast, thin crowds, and rates near the annual average. The main trade-off is that humpback whale watching has ended for the year and no major cultural festivals fall in May. If you prioritize uncrowded trails and calm snorkeling water over specific wildlife encounters, it's a good pick.
What is the weather like on Big Island in May?
It depends heavily on where you are. The island spans from sea level to well above 4,000 meters, so conditions vary by elevation. Along the Kohala Coast and in Kailua-Kona, expect warm afternoons in the upper 20s Celsius (low to mid 80s Fahrenheit). Higher-elevation towns like Volcano and Waimea are noticeably cooler, and the summit of Mauna Kea drops below freezing at night year-round. The eastern Hilo coast stays wetter than the west regardless of season.
Is Big Island crowded in May?
Not particularly. May is one of the quieter months. Mainland schools are still in session, and the winter snowbird season has ended. Popular spots like Hapuna Beach and the Kīlauea Iki trailhead rarely hit capacity outside of Memorial Day weekend. That holiday brings a short spike in domestic visitors, but it clears quickly by the following Tuesday.
Can you see active lava on Big Island in May?
It depends on Kīlauea's current activity, which follows no seasonal pattern. The volcano has had multiple eruptions since 2018, but also months-long pauses with no surface lava. Check the USGS Hawaiian Volcano Observatory website for real-time updates before your trip. Even without active flows, the steam vents, sulfur banks, and the Kīlauea Iki crater trail are worth the visit.
Is it too late for whale watching on Big Island in May?
Largely, yes. The North Pacific humpback population migrates through Hawaiian waters from roughly December through April. By May, the vast majority have headed north toward Alaska. A handful of stragglers might appear in the first week, but no responsible operator would guarantee sightings. The manta ray night snorkel runs year-round and offers a reliable marine wildlife encounter instead.
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