At a reflex level, trekking is a physical challenge: a simple desire to pick a path and measure up to the terrain and the elements. The adventure component adds the spice of uncertainty, raising the stakes for you to test yourself in unfamiliar territory.
On a deeper level, trekking is a bridge between ancient lifestyles: the fixed vision of a settler counterbalanced by the transient motion of a nomad. As an evolution from a simple walk into a more self sufficient venture, trekking requires simplification, a reduction to portable basics, and implicit trust in your ability to define what you need to live.
Because of the vastness of the terrain and altitude difference, trekking trips can be undertaken the whole year round. Treks range from low altitude treks in winter to the crossing of high passes in summer when the snowline recedes, It is also possible to combine all three-river running, trekking and mountaineering. The conventional trekking periods preferred are mid-April to May-June before monsoon and after the rains in the months of September-October-November.