I'd say the best time to visit Phuket is between November to March. The temperatures in May goes up to 36C. But either ways, you'll have a lot of activities in Phuket that could engage your time during your stay there. You caould go to the Phi Phi Island, Phuket FantaSea Show, Kayaking, Whitewater Rafting and Elephant Trekking, Phang Nga Bay Cruise, visit the Coral Island and a lot more. So you don't have to worry about the activities there. I am sure you would love it!! Anyways hope this helped.
HolidayIQ.com is a premier holiday information portal powered by India's first & biggest travel community; enabling travellers to first discover numerous vacation choices, then plan holiday trips in full detail and finally, share holiday experiences with millions of other travellers.