Summer: (May-August) is hottest season of Nepal. Hot but dry days are more comfortable than those of Monsoon days which are hot and humid.

Autumn: (September to November) begins with the end of Monsoon and ends with beginning of winter in November. It is also a festival season. You can enjoy lots of green and blue sky. Best season for out door activities like trekking, rafting, and wild life jungle safari.

Winter: Cold months are November till February. Winter days are also dry days with a few rains. Typical day of Katmandu valley in winter season is as warm as 20 degree Celsius in a sunny days but night temperature falls below freezing. The little rains in winter are due to Mediterranean activities. Hence the winter rainfall in western Nepal has more rain than those of eastern Nepal.

Spring: (February till April): Spring begins with occasional shower and rains. The days are mild days with the new vegetation. The sky is not as blue as Autumn. It is a little hazy if no shower for a long period.

The climate of Nepal is best assessed with the climate at 4 distinct places.
These are Katmandu valley, Pokhara valley (West), Chitwan (Terai), and Namche Bazaar (East & High mountain).

History
Before Nepal’s emergence as a nation in the latter half of the 18th century, the designation ‘Nepal’ was largely applied only to the Katmandu Valley. Thus up until the unification of the country, Nepal’s history is largely the history of the Katmandu Valley. References to Nepal in famous Hindu epics such as the Mahabharata, Puranas and also Buddhist and Jain scriptures, establish the country’s antiquity as an independent political and territorial entity. The Vamshavalis or chronicles, the oldest of which was written during the 14th century, are the only fairly reliable basis for Nepal’s ancient history. The Vamshavalis mention the rule of several dynasties the Gopalas, the Abhiras and the Kiratas — over a stretch of centuries. However, no extant historical evidence has yet authenticated the rule of these legendary dynasties. The documented history of Nepal begins with the Changu Narayan temple inscription of King Manadeva I (C 464-505 A.D.) of the Lichavi dynasty.

Lichavi Dynasty
The Lichavis are said to have migrated into Nepal from north India in around 250 A.D. The first Lichavi king of historical importance was Manadeva 1. Another important Lichavi monarch was Anshuverma who opened trade routes to Tibet. One of his daughters, Bhrikuti, who was married to Tibetan ruler Tsrong-tsong Gompo, was instrumental in spreading the Gospel of the Buddha in Tibet and China. Anshuverma has been referred to as a man of many talents in the accounts of the Chinese traveler Huen Tsang, who had visited India in the 7th century AD.

Narendradeval another Lichavi king initiated friendly relations with China and his successors laid the foundations of friendship with India by entering into matrimonial alliances with the Indian royal families. The Lichchhavi rule spanned over a period of about 630 years, the last ruler being Jayakamadeva.

Malla Dynasty
After the fall of the Lichchhavis came the Malla period during which the foundation of the city of Kantipur (later Katmandu) was laid. The early Malla rule started with Ari Malla in the 12th century and over the next two centuries grew into a large empire before disintegrating into small principalities which later became known as the Baisi (i.e. the twenty-two principalities). This was more or less coincidental with the emergence of the Chaubisi (i.e. twenty-four principalities). The history of these principalities remains shrouded up until the time when they joined other kingdoms, both large and small, to form the unified Kingdom of Nepal.