Located in the Lao Cai Province in Northwest Vietnam, 9 km southwest of Sapa Township in the Hoang Lien Son… Fansipan mountain is known as the roof of the Indochina. Are you going to climb Fansipan peak? and wondering what the best time is to climb? Best time to climb Fansipan mountain is: The best time to climb is between October and April. During the summer it is sometimes rainy but is still climbable if the weather holds. Now, no worry about the bad weather in case, Cable car travel will help you conquer the peak of 3143 meter quickly. The climate of Hoang Lien Nature Reserve is unique to Vietnam. It is highly seasonal, with a subtropical climate in the summer and a temperate climate during the winter. Mean annual temperature for Sapa town is 15.4 degree C, with a maximum of 29.4 degree and a minimum of 1 degree C. The warmest months are July and August, and the coldest month are December and January. Snow falls in some years on the highest peaks. In common with the rest of northern Vietnam,Hoang Lien Nature Reserve experiences a marked wet season from May to September, with the heaviest rainfall occuring in July and August. Mean annual rainfall is 2763mm, with a high of 4023mm and a low of 2064mm. Humidity ranges from 75 to 91 percent with a yearly mean of 86 percent. Climate varies considerably within the nature reserve. The prevalent wind direction for most of the year is west to east, leading to cloud formation on the upper slope of the Fansipan massif. These high-altitude areas are covered by cloud most days of the year and have very high humidity. Cloud also penetrates into the valleys but these areas are usually less humid than the mountain slopes. In the extreme east of the nature reserve, around Ban Ho village, mean temperatures are considerably higher due to the lower altitude of these areas.