There is no doubt about it this is a year round place to visit. You will find Tonsai village busy during the high season but less so the rest of time. There is so much to do from dusk until dawn, with a very relaxed life style. Rain isn't a really an issue here, paths are narrow and easy to walk around without getting too wet, there's no traffic or roads, and no rush to go from one place to another. Weather on Phi Phi remains fairly constant throughout the year, HOT, with a few months during the Low-Season that has scattered rain, but it's usually hot. Located between Phuket and Krabi province, technically making Phi Phi a Krabi Island, Phi Phi gets sheltered from major storms that come in from these places and are broken up by the open seas. Although the weather does vary from season to season, some rain and storms from April through September, but never fear, Phi Phi rains start fast and are usually gone as soon as they started. Occasionally, you will get full days of solid rain but that is vary rare and near non existent during the peak season. The average temperatures for Koh Phi Phi is around 30 degrees celsius year round. So no matter what time you visit, it's usually very comfortable. The weather from April to June is the hottest times to visit, with April tending to be the hottest. May until October is considered the Low-Season or rainy season, It does sometimes rain a lot. Sometimes during the Low-Season it can seem like the rain will never stop, and if your holiday happens to coincide with those days, then its a bummer of a trip, its hard to tell for sure what the weather will be, being on an island there is no weather station so we rely on Phuket and Krabi's forecast If you don't want rain at all, or maybe only a little, so you can spend your time chilling in the sun, come during November to February. If you want to risk the chance of some rain but want to experience the island with less tourists and often cheaper prices, come anytime from April through September If you are coming to Phi Phi during peak season (November through February) it is highly recommended to reserve a room a few months in advance. If you just show up on this island and expect to find a decent room then you will more than likely be disappointed. During the summer, from May to October the sky occasionly will have clouds but the rain is never too strong here. The island doesn't have high hills that attract large clouds, you can always find a good place sheltered from the wind and the sea is always clear and blue offering year round great snorkelling and boat tours. The climate is very similar to Phuket with rains concentrated more between middle of September to the middle of November. From December to April there is no rain and the sea is completely flat from January to May. The best time to come is in September, because there are less visitors, the sea conditions are generally calmer and often it doesn't rain all month and the rates are low because it is considered off season.