One of the most common questions I am asked is when is the best time to visit Tibet? Well, that is a bit difficult to answer because there are pro's and con's to each season. What I will do is take each season and list the pro's and con's about them to help you decide when the best time is for you to visit the Land of Snows.
The summer season is the warmest time of year across the Tibetan Plateau. While it is still common for snow to fall on the northern Tibetan Plateau during the summer, especially in areas above 4000m, most places where travelers go to are mild and comfortable. Because of the mild temperatures across Tibet during the summer, this is the most popular time of year for travelers to come. Since the start of the train to Tibet in 2006, tourists numbers have increased nearly every year (exception was in 2008 when widespread riots took place across Tibet). Because of this, getting train tickets to Lhasa are difficult to get during the summer season. Also, tour and hotel prices are higher in Lhasa during the summer compared to the low season.
While the weather during the summer months are mild for the most part, the summer does bring rain and clouds. The rain is not nearly as much as what the south side of the Himalaya's get, but it does rain in Tibet during the summer. It won't rain everyday, but it will rain a few days each week in most regions. Even though it does rain, it is still possible to trek in Tibet during the summer. Also, the cloud cover is often thick so getting clear views of Everest and the Himalaya's are not as common as they are during the rest of the year.
If you are interested in seeing nomad Tibetan culture, the summer is the best time of year. The grasslands are an amazing color of green and thousands of Tibetans living in their yak wool tents can be found. In my opinion, if you hate cold weather, then the summer is the season for you to visit Tibet. However, if you don't mind a bit of cold weather, the skies are much clearer the rest of the year and will reward you with amazing views of the mountains.
The fall season is a great time of year to visit Tibet. The rainy season normally ends in mid to late September. The skies from then through early December are generally clear and the mountains are usually snow-capped. The temperatures are not as mild as the summer, but are still comfortable for most people. There will be freezing temperatures in most areas of Tibet, but with appropriate clothing, you will be fine. The tourists crowds have usually departed from Lhasa by mid-October making the Tibetan quarter much quieter. Also, nomad Tibetans can still be found living in tents across the grasslands. Overall, the fall is probably my favorite time of year for traveling across Tibet.
Some people may think I am crazy for saying this, but winter is a great time of year to visit Tibet. Here is why I think this....the weather is clear almost everyday giving amazing views of the mountains, hotels and travel agencies offer discounts during this time, there are almost no tourists around, the weather is probably not as cold as you think it will be and most importantly, Lhasa is filled with Tibetan pilgrims from all corners of Tibet. During Losar (Tibetan New Year), which takes place in the winter, thousands of Tibetan pilgrims pour into Lhasa on pilgrimage. It is an excellent time for photographers to visit Tibet to capture images of Tibetan nomads from the most remote regions of Tibet.
Over the last 7 or 8 years, Lhasa has an average high temperature of 9.5C (49F) during the winter months and an average low of -4C (24F). While I agree that these are not Southeast Asia or Caribbean-like temperatures, they also are not nearly as bad as most people think (most Chinese tourists are convinced that Lhasa is -40C in the winter). With the intense sun, the temperature during the day feels much warmer than what it actually is. The guesthouses in the Everest region and in western Tibet do get cold at night so bringing good quality winter clothing is important. Now the nomadic regions in northern Tibet in the Amdo and Kham regions do get cold....really cold! These areas can be visited in the winter, but if you don't like the cold, it is best to visit these when the weather is warmer.
Each March, most of the Tibetan Plateau closes to foreign tourists for 5 or 6 weeks. This is an annual closing that takes place each year. The reason is that March is a sensitive month to Tibetans, as it is the anniversary of the Dalai Lama fleeing to India in 1959 as well as many uprisings and protests in the past (most recently in 2008). Travel permits normally stopped being issued in late February or very early March and the region normally reopens in early April. The Amdo and Kham regions, which do not require travel permits or organized tours, usually also close to foreign travelers during this time.
Besides the annual closing of the Tibetan Plateau, the spring season is a good time to visit Tibet. The weather is generally clear until around mid to late May, the temperatures are crisp, but not frigid and there are not too many tourists around Lhasa.