Phuket is Thailand's largest island and the heart of its Andaman Sea coast. It is a 50-kilometre-long island connected to the mainland by bridge, big enough to feel varied: party-strip beaches at Patong, family-friendly resorts at Karon and Kata, sleepy coves at the south and north ends, and an interior of jungle and rubber plantations. The climate is tropical and ruled by the southwest monsoon, which is the single most important variable in planning a trip.
November through April is the dry season — sunny, calm sea, peak prices. May to October is the wet monsoon: cheaper, lush, often surprisingly sunny in the morning, but with rough surf and the occasional washed-out day.
December through February are the postcard months: 30-32°C days, low humidity, almost no rain, and the Andaman Sea calm and clear for snorkelling and island-hopping to Phi Phi and the Similans. Christmas and Chinese New Year are the busiest fortnights.
March and April stay dry but humidity climbs. April is the hottest month, with highs touching 34-35°C and sticky evenings. The Songkran water festival in mid-April is a wild three-day water fight. Late April brings the first monsoon rains.
May through September is the southwest monsoon. Daily heavy showers, often in late afternoon, with sunshine in between. Sea on the west coast becomes rough — many beaches fly red flags and swimming is unwise. Snorkelling visibility drops.
October is the tail of the monsoon — still wet but easing. November sees the dry season return mid-month and high-season pricing begins. By late November the sea has calmed and conditions are back to postcard.
Depends on priorities. Prices drop 30-50%, the island is greener, and mornings are often sunny. Downsides: rough sea on the west coast, closed national parks, and the chance of losing a day to a storm.
Phuket is the biggest, most developed and easiest to fly to. Krabi is more dramatic scenery and cheaper. Koh Samui is on the Gulf of Thailand and has an opposite monsoon — its rainy season is October-December when Phuket is sunny.
Generally safe but with two specific risks: drowning at the beaches in monsoon, and scooter accidents. Both account for far more tourist deaths than any crime.
Karon and Kata Noi have long, gently shelving sand and lifeguards. Kamala is calmer and more residential. Patong is loud and not ideal for young children.