How the Two Monsoons Work

The south-west monsoon runs roughly from May to October. It blows moist air off the Indian Ocean onto west-facing coasts: Thailand’s Andaman side, the west coast of peninsular Malaysia, Sri Lanka’s south-west, Myanmar, and most of the Philippines. During these months the east-facing coasts sit in a rain shadow and enjoy their driest weather.

From November to March the pattern reverses. The north-east monsoon brings rain to the Gulf of Thailand islands, Malaysia’s east coast, eastern Sri Lanka, and Vietnam’s central coast, while Phuket, Krabi, Langkawi, and Bali’s dry season all peak. Indonesia sits far enough south that it follows a simpler pattern: broadly dry from May to September and wet from December to March, with Bali and the Nusa Tenggara islands being the driest of all.

The Thai Meteorological Department and Indonesia’s BMKG publish seasonal outlooks that are more useful than generic weather apps, which tend to show a rain icon for every day in the tropics regardless of how much actually falls.

May to June: The Shoulder Sweet Spot

Late May and June are arguably the best-value weeks of the entire year. The north-east monsoon has fully cleared from the Gulf islands, the south-west monsoon has only just begun on the Andaman side, and school holidays in Europe and Australia have not yet started. Koh Samui, Koh Phangan, and Koh Tao are dry and calm, Bali and Lombok are entering their driest stretch, and Vietnam’s central beaches around Da Nang and Hoi An are hot and sunny.

Phuket and Krabi are still very workable in May. Rain typically arrives as a late-afternoon storm that clears by dinner, and the sea is usually swimmable on the sheltered east-coast beaches. By late June the Andaman swell picks up and red flags become common on west-facing beaches such as Kata and Nai Harn.

• Best picks: Koh Samui, Koh Tao, Bali, Lombok, the Gili Islands, Hoi An, Da Nang.
• Still fine with caveats: Phuket east coast, Krabi, Langkawi (afternoon storms).
• Starting to avoid: Koh Lipe and the Similan Islands, which close to boats from mid-May.

July to August: Follow the Gulf and the Indonesian Archipelago

This is peak season for many Western travelers, and the wettest stretch on the Andaman coast and in the Philippines. The good news is that the dry half of the region is very large. Thailand’s Gulf islands are at their best, with Koh Samui recording its lowest rainfall of the year in July and August. Malaysia’s east-coast islands, including Redang, Perhentian, Lang Tengah, and Tioman, are in the middle of their short dry season, with excellent visibility for snorkeling and diving.

Indonesia is the safest large-scale bet. Bali, Lombok, the Gilis, Sumba, Komodo, and Flores all sit in their dry season. Expect cooler evenings, low humidity, and manta-ray season in Nusa Penida and Komodo. See our best time to visit Raja Ampat guide for the one Indonesian exception: Raja Ampat is best from October to April, so skip it in the northern summer.

Central Vietnam is another strong option. Da Nang, Hoi An, and Nha Trang are hot and dry, and the luxury resorts along the coast are quieter than they are during the Tet and spring holidays. Avoid Phu Quoc, which sits in the Gulf of Thailand’s wet corner and gets its heaviest rain from July to September.

September to October: The Transition Months

September is the most unpredictable month. The south-west monsoon is weakening but still active on the Andaman side, and the Gulf islands begin to see their first heavy showers from late September. Indonesia remains dry through most of September, and Bali in particular is quieter and cheaper than in July and August with almost identical weather.

October is when the map flips. Phuket, Krabi, and Langkawi dry out rapidly through the month, with late October often bringing the first fully sunny weeks of the new high season at shoulder prices. Meanwhile Koh Samui and the Malaysian east coast enter their wettest period, which runs from October to December. Many Perhentian and Redang resorts close in late October and do not reopen until March.

If your dates fall in early October, Bali, Lombok, and the Nusa Penida area remain the safest choice. If they fall in late October, the Andaman coast becomes the better bet, and shoulder rates at the big Phuket and Khao Lak resorts are excellent.

November: The Reset

By November the Andaman coast, Langkawi, and Bali’s neighboring islands are largely dry, and the Maldives is entering its high season. The Gulf islands are at their wettest, with Koh Samui typically receiving more rain in November than in any other month. The Philippines is also transitioning, with Boracay and Palawan drying out through the month but still exposed to late-season typhoons.

Bali begins its wet season in November, although the first weeks are usually a gentle build-up rather than a hard switch. Sri Lanka’s south-west coast is in a short shoulder period before its dry season kicks in from December. For Maldives-bound travelers on a budget, our best time to visit the Maldives on a budget guide covers how November shoulder rates compare with December peak pricing.

Month-by-Month Comparison Table

The table below summarises the best and worst picks for each month of the rainy season. Ratings are based on average rainfall, sea conditions, and resort availability rather than on temperature, which stays between 28 and 33 degrees Celsius across the region all year.

How Luxury Resorts Price the Green Season

Most five-star groups in the region now market the wet months as the green season and price them aggressively. Typical published discounts at properties in Phuket, Khao Lak, Bali, and Langkawi run 25 to 45 percent below high-season rates, and many packages add a free night on a four-night stay, resort credit, or a complimentary half-board upgrade.

The catch is that some of the region’s most photogenic properties simply close. Resorts on the Similan and Surin islands, Koh Lipe, the Perhentians, and Redang typically shut for three to five months, and boutique dive resorts on Malaysia’s east coast follow suit. Always check the resort’s own website rather than a booking platform, which may still show availability for a closed property. For the Thai side, our Surin Islands timing guide explains the park-closure calendar.

The Philippine weather agency PAGASA issues typhoon advisories that should be checked before any Philippines booking between July and November; a single typhoon can close Boracay or El Nido for several days.

Packing and Planning for Wet-Season Luxury Travel

A wet-season trip rewards a little planning. Book a room category with a covered terrace or a private pool so an afternoon shower does not mean losing the outdoor space you are paying for. Choose resorts with strong indoor facilities, including a spa, a serious restaurant program, and a kids’ club if you are traveling with children. Plan boat trips and island-hopping for the morning, when seas are calmest, and keep afternoons flexible.

• Pack a lightweight rain shell and quick-dry footwear rather than an umbrella, which is useless in a tropical downpour with wind.
• Bring reef-safe sunscreen; UV is just as strong on an overcast day.
• Book refundable rates or a flexible cancellation policy where possible.
• Allow an extra buffer day before international flights if you are relying on ferries.

Frequently Asked Questions