Phuket Weather Forecast by Accuweather
The Accuweather website is one that I have found to have fairly accurate forecasts. The Phuket weather forecast page is here. Forecasts for Phuket do tend to be rather inaccurate or vague. Weather can be changeable here especially in the months May to October. And rain / thunderstorms can be quite localised. Might be wet in one part of Phuket, but not another. So to give a forecast or a current weather report for "Phuket" can be misleading. The island is hilly which affects weather, and Phuket covers over 500 square km, so it's very common for one end of the island to have different weather to the other. Anyway - Accuweather is not bad! Check the Phuket weather widget below.
You can get Accuweather weather widgets for your website here.
Phuket Weather Forecast by Accuweather | The Phuket Weather Blog
More About Phuket : Jamie's Phuket Blog