Geography of Nepal, It’s believed that a sea existed about 100 million years ago in the region of Nepal. According to the theory of plate tectonics, India and Tibet began to collide at least 50 million years ago. This plates within the earth’s crust create mountains where they collide. Approximately 40-45 million years ago, the northbound India plate began to force up the Tibetan plateau. The Himalayan chain was formed some 20 million years ago and continues to rise to this day.

From the Hindu Kush range of Afghanistan and Pakistan in the west to the Indian states of Arunachal Pradesh in the east, the Himalaya form an unbroken chain of over 2500km that divides the plains of India from the Tibetan plateau. The country of Nepal is approximately 800km long and 250km width, with some variation from east to west . Makalu, Kanchanjanga, Everest, Lhotse , Manaslu, Annapurna and Dhaulagiri, all exceeding 800mtrs in height, are the country’s highest peaks.

Rising abruptly from the plains of India are the step but fragile Siwalik Hills. The forested Mahabharat Hills, towering to over 3000m. mark the southern edge of the middle hills of Nepal, where most of the rural population live. The rolling hills are characterised by impressive terraces and dotted with quaint farmhouse. The valleys of Kathamandu and Pokhara are in this area. Further north are the rocky buttresses and sheer-sided canyons the form the immediate foundations of the great ice peaks. The main Himalayan range is not a watershed but cut by raging, fast-flowing rivers that allow access to the higher valley. The watershed is north of the Nepal Himalaya in Tibet.

The altitude range of the region varies from 600mtrs to 8848mtrs, the summit of Mt. Everest, although most Trekkers will reach a maximum height of 5550mtrs. Trails are rarely undulating or flat, so all visitors need to be relatively fit for a trek in Nepal.

Climate:

The climate of Nepal is influenced heavily by the Himalaya, a natural barrier that divides the main weather systems of Asia. The Indian plains to the south are generally hot and dry, while north India has coler, high pressure-dominated winters. During the India, North of the Himalaya, the mountains create a rain-shadow, making the climate in Tibet sunny, but harsh, cold and windy. As a general rule, throughout autumn and Spring, the temperatures on the southern slopes of the Himalaya range from 10°C to 30°C. North of the great mountain barrier, the temperature will range from 15°C down to -10°C and colder at night. The spring season after early April will have generally higher temperatures and more wind. During the monsoon, temperatures rarely dip below freezing, except in the highest meadows. Annual precipitation is normally less then 500 millimeters.

The Kathamandu valley has a pleasant climate with average summer and winter temperatures of 17°C – 32°C and 2°C – 12°C respectively.
Good to know is that on average temperatures drop 5°C to 6°C for every 1,000 m you gain in altitude.

There is no seasonal constraint on traveling in and through Nepal. Even in December and January, when winter is at its severest, there are compensating bright sun and brilliant views. As with most of the trekking areas in Nepal, the best time to visit are during spring and autumn. Spring is the time for rhododendrons while the clearest skies are found after the monsoon in October and November. However, Nepal can be visited the whole year round.