Although geographically quite small, Bhutan’s weather varies from north to south and valley to valley, mainly depending upon the elevation. In the North of Bhutan on the borders with Tibet it is perennially covered with snow. In the western, central and eastern Bhutan (Ha, Paro, Thimphu, Wandue, Trongsa, Bumthang, Trashi Yangtse, Lhuntse) you will mostly experience European-like weather. Winter lasts here from November to March.
Punakha is an exception as it is in a lower valley and summer is hot and winter is pleasant. Southern Bhutan bordering with India is hot and humid with a sub-tropical climate. While the monsoon affects northern Indian it does not command the same influence in Bhutan. Summer months tend to be wetter with isolated showers predominately in the evenings only. Winter is by far the driest period while spring and autumn tend to be pleasant.
There are four distinct seasons similar in their divisions to those of Western Europe. Temperatures in the far south range from 15°C in winter (December to February) to 30°C in summer (June to August). In Thimphu the range is from -2.5°C in January to 25°C in August and with a rainfall of 100mm. In the high mountain regions the average temperature is 0°C in winter and may reach 10°C in summer, with an average of 350mm of rain. Precipitation varies significantly with the elevation. The average rainfall varies from region to region.