The Namtso Lake is held as “the heavenly lake” or “the holy lake” in northern Tibet. Lying at the foot of Nyainqentanglha Mountain, it covers an area of 1,940 square kilometers at an elevation of 4,718 meters. or 15,479 ft! It is believed to be the largest saltwater lake in Tibet and at the highest elevation in the world.
A legend says Namtso is the daughter of the god Indra (the mythological king of the abode of the gods) and the wife of Nyenchen Tanglha (念青唐拉). The goddess of the lake has a cyan body, three eyes, and two hands, with an aquarium on her right hand and a mirror on her left. Her hair is raised in a high bun with the other hair falling on her back. She rides a blue dragon and is quite charming.
A day trip is often recommended as the weather at night can be harsh and cold. It is cold there, even in summertime, so take a thick coat to keep warm, and hot drinks in vacuum flasks. http://www.chinahighlights.com/nagqu/attraction/lake-namtso.htm
There is no hotel accommodation at Namtso, but there is a campsite with limited electricity and running water. You can find hotel accommodation in the town of Damxung, 2 hours away on the Lhasa road.
The low oxygen content can easily cause altitude sickness, especially in the morning, so do not do any strenuous activities. For example, when you are taking photos, do not squat down and stand up too quickly. Lake Namtso is quite a distance from Lhasa city, and 1,000 meters higher, so take some altitude medicine and oxygen with you in case of emergency.
We went in the month of May and it was perfect! Blue skies, bluer water. It was full of life. The local nomads busy ing themselves with their summer chores. It is about a 3-4 hour drive to the lake. There are no hotels so a day trip is recommended. You do have tents if you are ready to brave the cold. They do have a very nice restaurant that is clean and serves piping hot delicious Chinese food. They have decent restrooms for tourists and cell phone reception all the way!