The best time to visit is from April to September. Although, each season has its own special qualities and surprises. During this period the temperature is ranging from 15-25 Degree Celsius, it is not a raining season in Sapa so the trekking routes are dry and bear great opportunity to do longer treks and to conquer Mount Fansipan. During the winter months, the temperature is much cooler and it is advised to bring a some warm clothing (hat, sweater, wool socks) for your trekking. Also, during the winter months there are periods of light rain, sleet which brings in the fog. This puts Sapa in the clouds and allows for some fantastic photo opportunities. Tip: If you could not visit Sapa during a certain time, there are always some alternatives near Hanoi to visit. Excellent value you will find from Travel Desk of Sunny Sapa Hotel.