Within the diverse terrain of Himachal Pradesh are several parallel physiographic regions corresponding to the northwest-southeast-trending ranges of the Himalayan mountain system. The region adjacent to the plains of Punjab and Haryana consists of two stretches of the Siwalik (Shiwalik) Range (the Outer Himalayas) separated by long, narrow valleys. Elevations in the southern tract of the region average about 1,600 feet (500 metres), while in the northern tract they range between 3,000 and 5,000 feet (900 and 1,500 metres). To the north of the Siwaliks are the Lesser (or Lower) Himalayas, which rise to about 15,000 feet (4,500 metres). Within this region are the spectacular snow-capped Dhaola Dhar and Pir Panjal ranges. To the north again is the Zaskar Range, which reaches elevations of more than 22,000 feet (6,700 metres), towering over the other ranges in the region. Many active mountain glaciers originate in this area.

Himachal Pradesh has many perennial snow-fed rivers and streams, in addition to four major watercourses. The eastern portion of the state is drained primarily by the Sutlej River, which rises in Tibet. Draining the western part of Himachal Pradesh are the Chenab (Chandra-Bhaga), Ravi, and Beas rivers, which have their source in the Great Himalayas.

The Siwalik region has hot summers (March to June), with temperatures rising above 100 °F (38 °C), cool and dry winters (October to February), and a wet season (July to September), with rains brought by the southwestern monsoon. As elevations increase farther north, the climate becomes wetter and cooler. In the Great Himalayas, winters are bitterly cold and snowy, with temperatures dropping below 0 °F (–18 °C).