普吉今日：海况、天气、空气与开放情况

What is measured, and where

Everything above is a measurement with a time on it. The weather figures come from the Open-Meteo forecast API at a land point on the west of the island (7.89°N 98.3°E), which is the same grid the site's eleven-year climate normals are built on, so a reading here can be compared with the month's median without switching sources. The sea comes from the Open-Meteo marine model at two points: 7.99°N 98.28°E, off 邦涛 and 拉扬 on the exposed west coast, and 7.78°N 98.31°E off the southern end of the island, behind the headland that shelters 奈汉 and 拉威. PM2.5 comes from Air4Thai station 43t at the Municipal Health Center in Talat Yai, 普吉镇 — the Pollution Control Department's reference monitor for the province, and the only continuous PM2.5 instrument on the island whose hourly data is published.

A model is not a buoy. Wave height here is the significant wave height the marine model computes for a grid cell a few kilometres offshore, not the shore break you will actually stand in: a bay facing away from the swell will be flatter than the number, a headland or a reef pass rougher. The air-quality monitor sits in the middle of 普吉镇, ten to fifteen kilometres from the west-coast beaches, so it describes traffic-side air rather than beach air. The temperature is a two-metre air temperature over land and will read lower than a car park in the sun and higher than a shaded terrace above the water. Those limits are the reason this page prints figures and their sources instead of a single word like “good”.

How the sea reading works

The site draws its line at 1.5 metres. That is not a number chosen for this page: the monthly climate dataset counts a “rough-sea day” whenever the modelled daily maximum wave height off the west coast reaches 1.5 m, and the best-time-to-visit page ranks the months of the year on how many of those days a median month has. Using the same threshold here means the day and the month cannot contradict each other — a day this page calls rough is exactly a day that would be counted as rough in the annual table. Below 0.8 m the west coast reads as flat; between 0.8 and 1.5 m there is a working swell.

The line on this page is our reading of a modelled wave height, and nothing more. Real flags on Phuket beaches are raised by the lifeguard service on the sand, which watches the water rather than a model and takes account of rip channels, tide and how many people are in the sea. Where the two disagree, the flag on the beach is right and this page is wrong. Phuket loses swimmers every monsoon season, almost always on the west coast, almost always past a red flag, and usually within a few hundred metres of a lifeguard tower — so the practical rule is simpler than any number: if a red flag is flying, the sea is closed, whatever a website says.

Reading the day, not the season

Today falls inside the south-west monsoon, May to October, when the swell arrives on the west coast and the rain arrives everywhere. A season is a statement about a median month, and any single day inside it can behave like the other half of the year: December days with a metre of swell exist, and so do calm, blue August afternoons. That is the whole reason for a page like this one — the monthly page tells you when to book a flight, this one tells you what to do after breakfast.

The three-day forecast above is the modelled outlook for the same points, and its usefulness falls off with distance: tomorrow is close to reliable for rain totals and wave height, the third day is a direction rather than a promise. Rain in Phuket is convective — an hour of very heavy rain and then sun, rather than a grey day — so a day carrying twenty millimetres is not a day indoors, it is a day with a plan that can pause. The seasonal statuses (Similan Islands and Maya Bay (Phi Phi Leh)) come from the tour catalogue that prices the island's day trips, so an opening date shown here is the same date the tour pages use.

What this page will never do

It will not price anything. The Phuket Travel Price Index measures hotels, villas, transfers, tours, rentals and daily budgets on the 1st and the 15th of each month, at a fixed booking horizon, and publishes medians with sample sizes; a hotel median does not change because it rained, and pretending otherwise would make the index worse rather than the page better. It will not invent a figure either: when a source is unreachable the block keeps the last measurement and is marked as such, and a value that has never been read is an em dash. And it will not turn readings into adjectives — the whole page can be checked against its own sources, which are named in the text and listed with their licences on the sources page.