Map from Google - Tibet

The vast plateau of Tibet, the "roof of the world", spans a larger area that goes beyond the political boundaries of the Chinese autonomous region of Tibet (Xizang), since it also includes much of the neighbouring Qinghai Province, which lies to the east. This area has a fairly uniform climate: cold and windy but dry in winter, and mild or cool in summer, with considerable variations between night and day, because of the strong sun rays of high altitudes. The north is a bit colder than the south, but above all the temperatures vary with altitude; the only significant difference between the areas is that the eastern part is affected by the summer monsoon, so that it receives a bit of rain (sometimes abundant) in summer. Even Lhasa, the capital, is located in the eastern part of the province, while all the central-western part of is virtually uninhabited since it's desert. While during winter Tibet is not the coldest part of China, it is in the other seasons due to the high altitude.
Lhasa is located at 3,500 metres above sea level: at this altitude the air contains 68% of the oxygen that is found at sea level. In addition, at high altitudes the water boils at lower temperatures: it boils at 90 °C at 3,000 metres, at 87 °C at 4,000 metres, and at 84 °C at 5,000 metres. In Lhasa in winter the nights are freezing cold, and in colder nights the temperature can reach -15 °C, but during the day it almost always exceeds freezing. It should be remembered that we are at a low latitude (29 ° north), so the sun is quite strong even in winter, and also that winter here is the sunniest season. The cold is usually bearable, even because the air is dry, except when the wind blows: as already mentioned, Tibet can experience strong winds especially in winter. Despite the fact that the winter is dry, sometimes light snowfalls may occur. Summer in Lhasa is mild, quite cold at night, about 9/10 °C, while it's pleasantly warm during the day: the average is 23 °C in June, but the almost tropical sun, especially at an altitude so high, in summer is very strong. In the hottest days, the temperature can reach 27/30 °C, from May to August.
Here are the average temperatures of Lhasa.
Average temperatures - Lhasa
Min (°C)-10-7-315910981-5-9
Max (°C)791216192322212016118

Summer, however, is not always sunny: the summer monsoon brings rainfall from June to September; July is the rainiest month, with 120 mm of rain on average. Even Mount Everest is often covered with clouds, so in summer it's more difficult to spot.
Here is the average precipitation.
Average precipitation - Lhasa
Prec. (mm)11252570120125601021420


The vast regions of Tibet located at higher altitudes, and especially the ones located in the north, have a worse climate than the capital. Between 4,000 and 4,500 metres, the temperature often remains below freezing all day long in winter, while the minima normally drop to -20/-25 °C, but sometimes it can plunge below -40 °C, after the outbreaks of cold air from the north. Summer at this altitude is cold at night, with lows around 3/5 °C, and mild during the day, with highs around 15/17 °C. Here are the average temperatures of Nagqu, located north of Lhasa, at 4,500 metres above sea level.
Average temperatures - Nagqu
Min (°C)-21-18-14-9-32430-6-14-20
Max (°C)-3-137111516151382-2

Xining, located at 2,260 metres above sea level, is the most populous city of the Tibetan Plateau and the capital of the Qinghai Province. Here, the lower altitude is compensated by the higher latitude (the city is located at the north-eastern edge of the plateau), so that winter is colder than in Lhasa, while summer is a bit warmer: the average in January is -6.5 °C, and in July it's 18 °C. Here, 360 mm of rain per year fall, with a maximum of 80 mm in August, and very little rain (or rather snow) from November to March.
Average temperatures - Xining
Min (°C)-14-11-4269121182-6-12
Max (°C)14101620232424191472

As already mentioned, the western part of Tibet, even more arid and located at very high altitudes, which often exceeds 5,000 metres, is almost totally uninhabited.

When to go

The best time to visit Tibet is summer: in Lhasa and in the east you may prefer May and September to avoid the bulk of the summer rains, but at higher altitudes, and maybe in the western area which is dry, you may prefer the June-August period, to reduce the risk of cold nights (which, however, above 4,000 metres is inevitable). In spring and autumn, in Tibet the climate is variable, it can be very cold with possible frost and snow especially at night, while the days can be sunny and mild. Those who don't suffer from the cold can choose spring and autumn, to enjoy the clear skies that also allow to observe the high mountains in the distance.

What to pack

In winter: in Lhasa, warm clothes, fleece, hat, gloves, parka, with the possibility of removing the outer layer during the day. In the north and the highest peaks, big chill clothing, synthetic thermal long underwear, parka, Gore-Tex jacket, gloves, hat, scarf.
In summer: in Lhasa, spring/autumn clothes, t-shirts for hot days, sweater and jacket for the evening, sunscreen, sunglasses, raincoat or umbrella, scarf for the wind, hiking shoes. For the north and the mountains, long jacket for the wind, down jacket, hat, gloves, scarf. For overnight stays outdoors, sleeping bag, warm jacket.