Basically, the Tibetan climate is not as harsh as
many people imagine it to be. The best time of year
to be in Tibet is from April to the beginning of
November, after which temperatures start to plummet.
The central Tibet, including Lhasa, Gyantse,
Shigatse and Tsedang, generally has very mild
weather from April to November, though July and
August can be rainy - these two months usually see
around half of Tibet's annual rainfall.
October and November often bring some dazzling clear
weather and daytime temperatures can be quite
comfortable at Tibet's lower altitude.
The coldest months are from December to February. It
is not impossible to visit Tibet in winter. The low
altitude valleys of Tibet (around Lhasa, Shigatse
and Tsedang) see very little snow.
Spring does not really get under way until April,
though March can have warm sunny days and is not
necessarily a bad month to be in Tibet.
More specific information in different areas:
Lhasa - the border of Nepal/China : The Friendship
highway is basically in good conditions year around.
But from December to February, the thawed road could
make some trouble Besides, try to avoid August -
landslide could happen in the rainy season.
Mt. Everest Region : Early May and early October are
the best time to visit Mt. Everest. Due to the clear
weather, you have great chance to see Mt. Everest's
true face. From December to February, it's too cold
to go to this region. But the magnetism of Mt.
Everest always attracts people anytime of the year.
Ali (Mt.Kailash) : Even without climate
restrictions, this area is already inhospitable. Big
rain and snow could make the journey worse. However,
for those determined tourists, the appropriate time
is May, June, July, September and October.
Eastern Tibet : Don't touch this area in July or
August, the rain could ruin the road, and make
terrible landslides. While in winter, the road could
Northern Tibet : With the average altitude of
4,500m, this area offers very limited time for
tourists. Summer is the prime time to enjoy the
great plain in northern Tibet.