These are some current weather reports from towns across the Tibetan Plateau.
Tibet is a huge area encompassing nearly 1/4 of the total land area of China. Tibet has varying elevations and geography. The Changtang (northern Plateau) is one of the coldest, highest (over 4400m) and most barren areas of Tibet. Winter here is the harshest in Tibet with temperatures often getting down to -30C (-22F) or colder. Freezing temperatures occur even in the summer there.
Amdo (northeast Tibet) has huge rolling grasslands giving way to high mountain ranges and is home to many nomads. While Amdo is not as high as Changtang, winter is still long and cold. With an average elevation of over 3400m and sitting in the most northern region of Tibet, winter can come early. Freezing temperatures are common by mid-Septemeber. Amdo also gets more snow than most regions of Tibet. If you have ever seen a picture of Tibetan nomads in snow, chances are it was taken in Amdo. Winter temperatures can easily get to -20C (-4F) and the high areas of Golok Tibet Autonomous Prefecture can get to -30C. Summers are short, but pleasant in Amdo with temperatures getting up to 24C (75F) by mid-July (nights are still cold though).
Kham (east Tibet) has varying climates. Most of Kham sits lower than the rest of Tibet. Places like Chamdo, Bayi, Kangding, Zhongdian and Dege are all under 3300m. While winter in these places can still be cold, it is not nearly as cold as northern Tibet. In the summer these places usually receive a lot of rain. Summer temperatures can be warm or even hot at times. Night time winter temperatures are usually between -4 and 2C (25-35F) with highs between 6 and 10C (43-50F).
Northwest Kham (Yushu Prefecture, Nagchu Prefecture and NW Ganzi Prefecture) sit at an average elevation of over 4000m. Winter here is much colder than the rest of Kham. Some of the heaviest snow I have seen has been through northwest Kham...in July! Winter temperatures average between -15 and -25C (5 to -13F) at night and -6 to 2C (21 to 35F) in the day. Summers are usually nice (except for those occasional snow storms!) with temperatures between 16 and 22C (60 to 72F).
Central Tibet (Lhasa-Shigatse area) has the mildest winters in Tibet. Night time temperatures in winter average between -4 and 2C (25-35F) with day time highs between 8 and 14C (47-57F). Summer temperatures range between 20 and 25C (68-77F) in the day and 10 to 14C (50-57F) at night. Central Tibet can see a lot of rain in the summer, but very little snow in the winter.