Ha Long Bay General information A huge bay dotted with nearly 2,000 mostly uninhabited limestone cliffs and breathtaking views. Over millions of years, tectonic plates have slowly thrust the limestone above the water-line – waves lapping against the stone carved out vast, striking cavers and other geological formations, such as tunnel caves and uniquely shaped massifs. Over the years, Vietnamese fisherman began to see shapes in the stone massifs atop the islands and names the islands accordingly – “Turtle Island,” “Human Head Island” and “Chicken Island.” The core of the bay has an area of 334 km2 with a high density of 775 islets. The geo-diversity of the environment in the area has created biodiversity, including a tropical evergreen biosystem, oceanic and sea shore biosystem. The evolution of the karst in this bay has taken 20 million years under the impact of the tropical wet climate. Historical research surveys have shown the presence of prehistorical human beings in this area tens of thousands of years ago. The successive ancient cultures are the Soi Nhu culture around 18,000–7000 BC, the Cai Beo culture 7000–5000 BC and the Ha Long culture 5,000–3,500 years ago. Ha Long Bay has also marked important events in the history of Vietnam with many artifacts found in Bai Tho Mout, Dau Go Cave, Bai Chay. In 1994, the core zone of Ha Long Bay was listed by UNESCO as a World Heritage Site. Weather Summary From January to March is the spring time when the temperatures are around 13-20°C, which is pleasant for a day of relaxation. There will be sunlight during the day and in the morning and late afternoon you will experience a fog and drizzle. April to June, is when summer takes place, temperatures range from 29°C – 40°C and humidity begins to rise. The weather is not brutally hot yet but will you may be likely to experience rain fall. July through September, although quite hot and humid, brings crystal clear skies and emerald water. Temperatures range from 23°C – 34°C and there may be light rain but expect a lot of direct sunlight. This time is the rainy season so there is a high chance of storms and typhoons, however the rain tends to be quite short and does not normally last long. Ha Long Bay’s peak season for tourists is from October to December. Along with rainfall, the humidity level drops and temperatures are around 17°C to 21-°C