(1) Bases of Classification. The bases of Koeppen’s climatic divisions are temperature and rainfall. Koeppen puts the combination of temperature and rainfall into five types – A, B, C, D, and E.
(2) Besides the ordinary pattern of the combination of climatic elements, he paid attention to the seasonal variation of these elements. On these bases he sub-divided the main types into smaller regions.
Koeppen’s Climatic Regions of India.
The following climatic regions have been identified in India according to Koeppen’s Climatic Classification:
It has a small dry season and is of a tropical type. It is found in the Western Coast, south of Goa.
It is a high solar position in which dry season dominates. Such is found around Coromandel Coast.
It is also called tropical Savannah and covers most of the peninsular plateau, southern Bihar, Orissa, southern W Bengal and a narrow belt, west of Bangladesh.
It is semi-arid Steppe type of climate, where average annual temperature is above 18°C. It includes the southern part of Haryana, Rajasthan and the interior part of the Peninsula.
It is a desert type of climate. In this type of climate winters are dry and the average annual temperature is above 18°C. This climate is found in Western Rajasthan.
It is warm temperate rainy climate. The winter season is dry. The hottest month precedes solstices and the rainy season occurs in summer.
This type of climate is found in the northern plains from the eastern Rajasthan, U.P, Bihar, northern part of W.Bengal, northern part of M.P and the area surrounding the northern, eastern and southern part of north-eastern states.
Cool temperate wet forests climate, where rainfall takes place almost throughout the year. The summers are cool and the temperature of less than four months is above 10°C.
This type of climate is found mostly in the northern part of Arunachal Pradesh.
(8) E. The average temperature of the hottest month is below 10°C. In fact there is no summer season. It is dry and cold. The temperature of the winter season remains much below freezing point. It is found in northern Jammu and Kashmir.