An August morning in Kauai finds trade winds shaking the palms on the Kapaa shore, roosters crowing from beside the road, and the earliest surfers paddling out as clouds still cap the mountains. The island is green from the wet winter, the water is as warm as it gets, and school-break families fill the beaches by mid-morning. August is the month for snorkeling, waterfall country and long afternoons on the sand.
What is the weather like in Kauai in August?
August is warm, sunny and fairly dry on most of the coast, with the trade winds taking the edge off the afternoon heat. Showers are short and passing, and they are far more likely on the north shore and in the mountains than around Lihue or Poipu.
| Month | Average high (°F) | Average low (°F) | Rain days | Sea (°F) |
|---|---|---|---|---|
| July | 84.6 | 74.6 | 5.0 | 79.6 |
| August | 85.2 | 75.2 | 5.3 | 80.0 |
| September | 85.3 | 74.8 | 5.2 | 80.7 |
Mornings are the best hours for almost everything. The light is clear, the breeze is soft and the sun has not yet turned fierce, so hikes, boat trips and beach walks all fit before lunch.
By early afternoon it feels properly hot in the sun, and a shady table, a shave ice or a dip in the sea becomes the plan. Evenings stay warm enough for shorts and a t-shirt, and dinner outdoors is easy.
How much rain you get hinges on where you are on the island. Princeville and the north shore get far more of it, often as a quick shower rolling off the mountains that leaves a rainbow behind. The south and west, around Poipu and Kekaha, stay the sunniest. At Kokee, on the rim of Waimea Canyon, daytime temperatures sit in the low 70s and drop into the 50s after dark, a noticeably cooler feel that makes a light jacket welcome even in summer.
Days are long, with nearly thirteen hours of daylight, which leaves room for a full outing and a slow sunset afterward. Bring sun protection first and a thin rain layer second.
Can you swim in Kauai in August?
That’s right, the ocean is warm enough for a long and comfortable swim, and a wetsuit is not needed for snorkeling.
For the north and east shores, August tends to bring far calmer conditions than winter, when the surf is typically large, making summer the milder season. Hanalei Bay and the beaches around Anini tend to be friendlier than in winter, and the south shore at Poipu has sheltered spots that families like, though south swells can arrive in summer and raise the waves. On the east side, small children are well served by the rock-walled pools at Lydgate Beach.
Snorkelers head to Poipu, Tunnels near Haena and the calmer corners of Anini, and a morning start usually means clearer water and fewer people. Conditions change from one day to the next and from one beach to another, so before you get in the water, read the signs, follow the flags, and have a word with the lifeguard. Pack a rash guard, snorkel gear and lots of water, and stay a respectful distance away from turtles and monk seals, both of which are protected.
What to do in Kauai in August
August is high summer on the island, so the plan is built around the water in the morning and green, shaded places later in the day. The sea is at its warmest, the trails are mostly dry and the days are long. Locals spend weekends at beach parks with coolers, folding chairs and a ukulele, and a plate lunch from a roadside truck is the standard order: rice, macaroni salad and kalua pork or garlic shrimp.
Fruit stands and farmers markets fill with tropical produce, and shave ice with a scoop of ice cream underneath is the afternoon treat to look for. Towns like Kapaa, Hanapepe and Koloa have a relaxed, small-town mood, with art galleries, bakeries and a few evening events.
The Na Pali Coast by boat
The cliffs of Na Pali, fluted ridges falling straight into the sea, are one of the great sights of Hawaii, and in summer the ocean is usually more settled for boat trips than in winter. Boats leave from the west side, often early in the morning, and run along the coast past sea caves and waterfalls. Spinner dolphins and sea turtles are sometimes seen, and snorkel stops are common.
It suits most travelers who are comfortable on a boat, and a morning departure is better for the light and the calmer sea. Bring a hat, sunscreen and a layer for the wind, and take motion-sickness medicine if you are prone to it.
Waimea Canyon and Kokee
Waimea Canyon is the red-and-green gash that Mark Twain is said to have called the Grand Canyon of the Pacific. From the lookouts on the road up, the walls glow orange and rust, and waterfalls thread the far side. Higher up at Kokee, the air is cooler and the forest trails are pleasant on a summer day.
Head out early, before clouds fill the canyon, and set aside half a day for a picnic. The west side is the driest part of the island, so the odds of clear views are decent, though cloud can still roll in. Carry a light jacket and water.
The north shore: Hanalei and Haena
The north shore is the lush, postcard side of Kauai, with taro fields, a long curve of beach at Hanalei and mountains streaked with waterfalls. In August the bay is often calm enough for paddleboarding and kayaking, and the town has shops, food trucks and shaded lawns for a slow afternoon.
Beyond Hanalei the road narrows toward Haena, where beaches, caves and the start of the Kalalau Trail lie. Haena State Park requires a reservation, so plan that part of the day ahead and have a backup in Hanalei if you do not get one. Showers are more frequent here, so keep a light rain shell handy.
Smaller pleasures fill in the gaps: the Kilauea Lighthouse and its seabirds, the Wailua River and Opaekaa Falls, the Kauai Coffee estate near Kalaheo and the old plantation streets of Koloa. Nearly everything can be reached by car, and the loop road keeps drives short.
A two-day itinerary for Kauai in August
Day 1 is for the west and south. Start early with the drive up to Waimea Canyon and Kokee, when the lookouts are clear and the air is cool, and spend the morning on the rim and a short forest walk. Head down for a late lunch of fish tacos or a plate lunch in Waimea or Hanapepe, where the old wooden storefronts and galleries are good for a stroll.
By mid-afternoon, when the sun is strongest, settle on the south shore. Poipu has beaches for swimming and snorkeling, and monk seals or turtles sometimes rest on the sand, so keep your distance. Stay for sunset on the sand, then dinner in Koloa or Poipu.
Day 2 belongs to the north and the east. Leave early for Hanalei, with a stop at the Kilauea Lighthouse on the way, and have the beach morning when the water is usually calm and clear. If you have a Haena reservation, use it for the morning and walk the coastline there. Lunch at a Hanalei food truck or bakery, then drift back along the coast.
Finish in Kapaa or Wailua with a swim or a walk on the coastal path, then dinner in town. If the weather turns, spend the afternoon in a coffee shop, gallery or museum in Lihue, or at an indoor market, and save the beach for the next clear window.
Is Kauai busy in August?
Yes, August is a busy month, with mainland families on summer vacation and local school returning around the middle of the month, though Kauai never feels crowded the way Oahu can.
The beaches are fullest on weekends and in the late morning, and the popular spots, such as Poipu, Hanalei and Lydgate, are livelier than in spring. Rooms, condos and rental cars are in demand, and it is wise to book early for the first weeks of the month, when families are still traveling. Later in the month, after schools reopen, things ease a little and last-minute choices become easier.
Restaurants in Poipu, Princeville and Kapaa fill up at dinner, so a reservation for popular places is a good habit, and boat trips on Na Pali sell out ahead. Haena State Park requires a reservation, as do some other popular sites, so check the state park pages as you plan. The quietest hours are early morning and the hour before sunset.
What to pack for Kauai in August
Pack for sun, water and the odd shower, with one warm layer for the mountains.
- Mineral sunscreen and a hat, because the midday sun is strong and the law regulates which sunscreens may be sold.
- A rash guard and swimsuit, for long snorkeling sessions.
- A light rain jacket, for quick showers on the north shore.
- A fleece or light jacket, for Kokee and boat rides.
- Sturdy sandals or trail shoes, for muddy waterfall paths.
- A reusable water bottle, for hot days on the trail.
Good to know before you go
The Central Pacific hurricane season runs from June 1 to November 30, so August sits inside it, and it is worth following the forecast as your dates approach. Rent a car, since the island has little public transit, and book the Haena reservation and any boat trips before anything else. Lodging taxes add to the bill, and you will feel the main ones at checkout.
| Fee | Amount | Who pays |
|---|---|---|
| State Transient Accommodations Tax | 11.00% | Guests, on lodging |
| Kauai County Transient Accommodations Tax | 3% | Guests, on lodging |
| General Excise Tax pass-on (maximum) | 4.7120% | Customers, on purchases |
Kauai in August vs July and September
July feels much like August, with slightly cooler air and a sea a touch less warm. The crowds are at their summer peak in July, and the first half of August is similar. If you want the same weather with a few more people around, July is the natural shift, and the Fourth of July week is the busiest.
September is a shade warmer in the sea and the air, with similar rain, and it is quieter once school is back in session. Rooms and tables are easier to find, and the beaches empty out on weekdays. It also sits deeper into hurricane season, so keep an eye on the forecast. Late September can be a lovely time for those who prefer space.
Families tied to school calendars will stay with August or July, while couples and flexible travelers do well in September. If the north shore is the goal, any of the three works, because summer seas there are friendlier than winter ones.
Is August a good time to visit Kauai?
Yes, August is a very good month for families, snorkelers, paddlers and anyone who wants warm water and long, bright days.
It suits travelers who like to be in the sea, on a boat or on a trail, and who do not mind sharing beaches with other vacationers. It is less ideal for those who want empty beaches and the lowest demand for rooms, or who hope to see humpback whales, which belong to winter. Anyone chasing big-wave surf will also prefer the cooler months, since the north shore is generally calmer now.
On arrival, pick up the car, buy water and sunscreen, and sort out your Haena reservation and any boat trip first, since those are the pieces that sell out. Then start with an easy beach afternoon to settle in. What makes August special here is the warm water and the green island under a long summer light, with the north shore calm enough to paddle across Hanalei Bay.
Sources
- NOAA NCEI, monthly normals 1991-2020, station USW00022536, checked September 8, 2026
- Open-Meteo Marine API, average 2015-2024, checked September 8, 2026
- sunrise-sunset.org, sunrise and sunset calculated for the 15th of the month, checked September 8, 2026
- Hawaii Department of Taxation, Tax Announcement No. 2025-03 (Transient Accommodations Tax Law Changes from 2025 Legislative Session), files.hawaii.gov/tax/news/announce/ann25-03.pdf, checked September 24, 2026
- County of Kauai, Department of Finance, Transient Accommodations Tax page, kauai.gov/Government/Departments-Agencies/Finance/Transient-Accommodations-Tax, checked September 25, 2026
- Hawaii Department of Taxation, County Surcharge on General Excise and Use Tax page, tax.hawaii.gov/geninfo/countysurcharge/, checked September 25, 2026
- NOAA NCEI, monthly normals 1991-2020, station USC00518165
- NOAA NCEI, monthly normals 1991-2020, station USC00513099
- NWS Honolulu / Central Pacific Hurricane Center, « 2026 Central Pacific Hurricane Season Outlook », weather.gov/hfo/hurricaneOutlook2026, checked September 24, 2026
To plan your stay
- Things to Do in Kauai: Na Pali Views, Waimea Canyon, North Shore Beaches and Local Food
- Where to Stay in Kauai: Poipu, Princeville, the Coconut Coast and the West Side
- Kauai vs Oahu: Beaches, Things to Do, Weather and Getting Around
- Day Trips from Kauai: Waimea Canyon, Haena and the Na Pali Coast, Wailua and Polihale