Phuket

Phuket province wraps Thailand's largest island and the smaller mainland strip across the Sarasin Bridge channel, fronting the Andaman Sea on the country's south-western coast. The west-facing beach corridor at Patong, Karon, Kata, and Nai Harn runs the open ocean swell; the east-facing coast at Chalong, Phuket Town, and Ao Po shelters in the calmer Phang Nga Bay where the limestone karst islands rise straight from the water. The tide here is a moderate mixed semidiurnal signal: mean range at the Patong and Chalong gauges is about 1.6 metres, climbing past 2.7 on the largest spring tides and dropping near 0.8 on neaps. Two highs and two lows of unequal size each day, with the asymmetry shifting toward strongly diurnal at certain lunar phases. The defining seasonal force is the monsoon. The south-west wet monsoon from May through October drives onshore swell, rough surf, and frequent red-flag swimming bans on the west coast; the north-east dry monsoon from November through April flattens the same coast for the working dive industry and the Similan Islands tourist season. The 26 December 2004 Indian Ocean tsunami struck the Andaman coast within two hours of the Sumatran rupture with run-up heights at Patong reaching about ten metres and Khao Lak further north reaching closer to fifteen, reshaping the entire safety calendar of the Thai west coast and seeding the modern early-warning network. The Phang Nga Bay long-tail boats running tourists to Phi Phi and James Bond Island, the Phuket dive industry out of Chalong, and the working shrimp ponds in the inner mangroves all read the table for different windows. The Hydrographic Department of the Royal Thai Navy publishes the authoritative tide tables.