Koshi basin has been chosen because only a few significant studies have been conducted in the eastern part of Nepal related to climate classification that has substantial economic contribution. Climate type influences the tourism, agricultural, forest, water resources, human settlement and health, land use, population etc. With the global warming, the climate type study in this region can be further upgraded for adaptation and future application.
Koshi basin of Nepal extends from lowland of Terai plain in the south to the Himalayan ranges in the north. The altitude varies from 60 to 220 m in the south rising to 8848 m in the north. In general, the environmental lapse rate is considered as with 1 km increase in altitude ,there is a decrease in temperature by about 6 0 C. However, unlike temperature, Precipitation and relative humidity vary from one region to another both horizontally and vertically causing complex variation in climate like in Nepal. With the detailed climate classification in various parts of this basin, cash crop agriculture, tourist resorts, healthy settlement locations, etc. can be delineated for further planning.