Geography of Kerala

Kerala’s 38,863 km² (1.18% of India’s landmass) are wedged between the Arabian Sea to the west and the Western Ghats to the east. Kerala’s coast runs some 580 km in length, while the state itself varies between 35–120 km in width. Geographically, Kerala roughly divides into three climatically distinct regions. These include the eastern highlands (rugged and cool mountainous terrain), the central midlands (rolling hills), and the western lowlands (coastal plains). Located at the extreme southern tip of the Indian subcontinent, Kerala lies near the center of the Indian tectonic plate (the Indian Plate); as such most of the state (notwithstanding isolated regions) is subject to comparatively little seismic or volcanic activity. Geologically, pre-Cambrian and Pleistocene formations comprise the bulk of Kerala’s terrain. The topography consists of a hot and wet coastal plain gradually rising in elevation to the high hills and mountains of the Western Ghats. Kerala lies between north latitudes 8°18' and 12°48' and east longitudes 74°52' and 72°22'. Kerala’s climate is mainly wet and maritime tropical,heavily influenced by the seasonal heavy rains brought by the monsoon.

Climate
Kerala, which lies in the tropics, is mostly subject to the type of humid tropical wet climate experienced by most of Earth's rainforests. Meanwhile, its extreme eastern fringes experience a drier tropical wet and dry climate. Kerala receives an average annual rainfall of 3107 mm — some 7,030 crore m3 of water. This compares to the all-India average is 1,197 mm. Parts of Kerala's lowlands may average only 1250 mm annually while the cool mountainous eastern highlands of Idukki district — comprising Kerala's wettest region — receive in excess of 5,000 mm of orographic precipitation (4,200 crore of which are available for human use) annually. Kerala's rains are mostly the result of seasonal monsoons. As a result, Kerala averages some 120–140 rainy days per year. In summers, most of Kerala is prone to gale-force winds, storm surges, and torrential downpours accompanying dangerous cyclones coming in off the Indian Ocean. Kerala’s average maximum daily temperature is around 36.7 °C; the minimum is 19.8 °C.

Physiogeography
Eastern Kerala consists of land encroached upon by the Western Ghats; the region thus includes high mountains, gorges, and deep-cut valleys. The wildest lands are covered with dense forests, while other regions lie under tea and coffee plantations (established mainly in the 19th and 20th centuries) or other forms of cultivation. Forty-one of Kerala’s forty-four rivers originate in this region, and the Cauvery River descends from there and drains eastwards into neighboring states. Here, the Western Ghats form a wall of mountains penetrated near Palakkad; here, a natural mountain pass known as the Palakkad Gap breaks through to access inner India. The Western Ghats rises on average to 1500 m elevation above sea level. Certain peaks may reach to 2500 m. Just west of the mountains lie the midland plains, comprising a swathe of land running along central Kerala. Here, rolling hills and shallow valleys fill a gentler landscape than the highlands. In the lowest lands, the midlands region hosts paddy fields; meanwhile, elevated lands slopes play host to groves of rubber and fruit trees in addition to other crops such as black pepper, tapioca, and others.

Finally, Kerala’s coastal belt is relatively flat, teeming with paddy fields, groves of coconut trees, and heavily crisscrossed by a network of interconnected canals and rivers. The Kerala Backwaters region is a particularly well-recognized feature of Kerala; it is an interconnected system of brackish water lakes and river estuaries that lies inland from the coast and runs virtually the length of the state. These highly facilitate inland travel throughout a region roughly bounded by Thiruvananthapuram in the south and Vadakara (which lies some 450 km to the north). Lake Vembanad — Kerala’s largest body of water — dominates the backwaters; it lies between Alappuzha and Kochi and is over 200 km2 in area. The comparative water-richness of the coastal belt can be partly gauged by the fact that Kuttanad, with its backwaters canals and rivers, itself comprises more than 20% of India's waterways by length. The most important of Kerala’s forty-four rivers include the Periyar (244 km in length), the Bharathapuzha (209 km), the Pamba (176 km), the Kadalundipuzha (130 km), and the Achancoil (128 km). Most of the remainder are small and entirely fed by the Monsoons.

Districts
Fourteen districts comprise Kerala. The districts are distributed between Kerala's three traditional regions. Northern Kerala includes (from north to south) Kasargod, Kannur (Cannanore), Wayanad (Wynad), Kozhikode (Calicut), and Malappuram. Central Kerala includes Palakkad (Palghat), Thrissur (Trichur), Ernakulam (Cochin), and Idukki. Lastly, southern Kerala is composed of the five remaining districts: Alappuzha (Alleppey), Kottayam, Pathanamthitta, Kollam (Quilon), and Thiruvananthapuram (Trivandrum).

Mahe, a part of the union territory of Pondicherry, is an enclave within Kerala. Thiruvananthapuram is the state capital. Kochi is the largest city and considered the commercial capital of the state.