Koh Samui

Koh Samui is Thailand’s second-largest island at 228 square kilometres, sitting in the Gulf of Thailand 35 kilometres off the Surat Thani coast. It draws over 2.7 million visitors annually to its 50-plus beaches, coconut palm interior, and distinct weather pattern that differs from the Andaman coast: while Phuket and Krabi soak under the southwest monsoon from May to October, Koh Samui stays relatively dry, with its heaviest rains arriving November through December during the northeast monsoon.

The island has its own international airport (USM) with direct flights from Singapore, Kuala Lumpur, Hong Kong, and Bangkok, and a ring road (Route 4169) that circles the 51-kilometre perimeter in about 90 minutes. Chaweng Beach on the east coast is the island’s hub of restaurants, bars, and resorts; the north and west coasts are quieter, and the interior rises to 635 metres at Khao Pom peak.

Koh Samui Weather Overview

Koh Samui’s climate follows the Gulf of Thailand monsoon pattern rather than the Andaman one, which means it has three seasons and a different rainy period from Phuket and Krabi. The dry season runs December through February with clear skies, 30degC (86degF) highs, and calm seas ideal for boat trips to Ang Thong Marine Park.

March and April are the hot season, reaching 33degC (91degF) with rising humidity. The first rainy period arrives May through September with brief afternoon showers and plenty of sunny hours between them , this is actually an excellent time to visit with low hotel prices and uncrowded beaches.

The main rainy season hits October through December, with November typically the wettest month at 440mm across 20 rain days, when the northeast monsoon brings sustained heavy rain and rough seas on the east coast. Annual rainfall averages 1,960mm. Sea temperature stays at 28degC to 30degC (82-86degF) year round.

Koh Samui Seasonal Snapshot

• Dry Season (December to February): Sunny days at 30degC (86degF), 6 to 8 hours daily sunshine, calm seas. Peak tourist numbers, highest prices. Book 2 months ahead. Christmas and New Year at Chaweng Beach draw the biggest crowds.
• Hot Season (March to April): Temperatures to 33degC (91degF), increasing humidity. Songkran (April 13-15) brings island-wide water fights. Shoulder-season hotel rates make this a solid value window with mostly good weather.
• Mid-Year (May to September): Brief afternoon showers (140-180mm monthly), sunny mornings, uncrowded beaches, hotel prices 30 to 50 percent below high season. The sea stays calm enough for Ang Thong Marine Park trips. The best value-for-weather window on the island.
• Monsoon (October to December): Northeast monsoon peaks in November at 440mm rain across 20 days. Sustained downpours, rough seas on east-coast beaches. Many beachfront restaurants close October through mid-December. Ferry services to Koh Phangan and Koh Tao may be cancelled during storm warnings.

Koh Samui Quick Facts

• Best months: January to March and July to August (calm seas, good weather)
• Warmest month: April at 33degC (91degF)
• Wettest month: November at 440mm
• Driest month: February at 40mm
• Sea temperature: 28-30degC (82-86degF) year round
• Annual sunshine: Approximately 2,200 hours

Koh Samui Travel Guides

1. Best Beaches in Koh Samui: Chaweng, Lamai, Bophut, Maenam, Choeng Mon, Silver Beach, Lipa Noi , all 7 major beaches ranked with swimming conditions, facilities, and crowd levels by season.
2. Things to Do in Koh Samui: Big Buddha temple, Na Muang waterfalls, Ang Thong Marine Park kayaking, Secret Buddha Garden, Muay Thai at Chaweng Stadium, and sunset cruises.
3. Day Trips from Koh Samui: Ang Thong National Marine Park, Koh Phangan, Koh Tao snorkelling trips, and the full moon party shuttle.
4. Where to Stay in Koh Samui: Area guide covering Chaweng’s action, Bophut’s Fisherman’s Village, Lamai’s value strip, Maenam’s quiet retreats, and Choeng Mon’s luxury enclave. Suggested hotels for every budget in each area.
5. Getting Around Koh Samui: Airport transfers, songthaew routes along the ring road, motorbike rental safety, Grab availability, and ferry connections to Koh Phangan, Koh Tao, and the mainland.

Suggested Hotels in Koh Samui

Four Seasons Resort Koh Samui

Sixty pool villas cascading down a private hillside on the island’s northwest tip at Laem Yai, each with an infinity pool and Gulf of Thailand views. The resort’s beach stretches 200 metres of private sand and the Rum Vault hosts tastings of 30-plus Caribbean and Asian rums. Best for honeymooners and luxury travellers seeking total seclusion.

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Amari Koh Samui

Located on the quieter north end of Chaweng Beach with direct beach access, three pools, and Thai cooking classes at 1,200 THB per person. A 10-minute walk south reaches Chaweng’s restaurant and bar strip. Best for families and couples who want Chaweng’s convenience without sleeping above a nightclub.

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Lub d Koh Samui Chaweng Beach

A design hostel on Chaweng Beach with a beachfront pool, co-working space, private rooms, and dorm beds from 400 THB per night. The beachfront bar runs daily happy hours from 16:00 to 19:00. Best for solo travellers and backpackers who want a social, beachfront base with hotel-style facilities.

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