Went to Penang June two years ago. Weather was fine, not much in the way of rain, few downpours, which were shortlived and not every day. Other than that was hot and sunny. I will definitely agree with bleary about the rats in Georgetown. Size of cats and everywhere. If you go, dont spend long here. Beaches are ok, Batu Ferenghi is quite nice, but there are much nicer places to go. Perenthian Islands off the East Coast of Malaysia are a paradise. Fairly remote, generator electricity, no motor vehicles of any kind. Some nice places to stay and eat though, and the snorkelling just from the shore is beautiful. The water is also unbelieveably clear. Its mainly muslim so getting a beer is a bit of an adventure but it can be done! Spent a week there once and was never so relaxed in all my life.