Climate

The climate of India comprises a wide range of weather conditions across a vast geographic scale and varied topography, making generalisations difficult. Based on the Köppen system, India hosts six major climatic subtypes, ranging from arid desert in the west, alpine tundra and glaciers in the north, and humid tropical regions supporting rainforests in the southwest and the island territories. Many regions have starkly different microclimates. India's unique geography and geology strongly influence its climate; this is particularly true of the Himalayas in the north and the Thar Desert in the northwest. The Himalayas act as a barrier to the frigid katabatic winds flowing down from Central Asia. Thus, North India is kept warm or only mildly cooled during winter; in summer, the same phenomenon makes India relatively hot. Although the Tropic of Cancer-the boundary between the tropics and subtropics-passes through the middle of India, the whole country is considered to be tropical.

Seasons

The nation has four seasons:

• Winter (January and February)
• Summer (March to May)
• Monsoon (rainy) season (June-September)
• Post-monsoon period (October-December)

Winters start in November in northern India and late December in southern India. Winters in peninsula India see mild to warm days and cool nights. Further north the temperature is cooler. Temperatures in some parts of the Indian plains sometimes fall below freezing. Most of northern India is plagued by fog during this season.

Summer lasts between March and June in most parts of India. Temperatures exceed 40°C (104°F) during the day. The coastal regions exceed 30°C (86°F) coupled with high levels of humidity. In the Thar desert area, temperatures can exceed 45°C (113°F).

Summer is followed by the southwest monsoon rains that provide most of India with its rainfall. The rain-bearing clouds are attracted to the low-pressure system created by the Thar Desert. The official date for the arrival of the monsoon is 1 June, when the monsoon crosses the Kerala coast. The southwest monsoon splits into two arms, the Bay of Bengal arm and the Arabian Sea arm. The Bay of Bengal arm moves north-wards crossing northeast India in early June. It then progresses eastwards, crossing Delhi by June 29. The Arabian Sea arm moves north-wards and deposits much of its rain on the windward side of Western Ghats. By early July, most of India receives rain from the monsoons.

The monsoons start retreating by August from northern India and by October from Kerala. This short period after the retreat is known as the retreat of the monsoons and is characterised by still weather. By November, winter starts setting in the northern areas.

Temperatures

The highest temperature recoded in India was 50.6°C (123.08°F) in Alwar in 1955. The lowest was -45°C (-49°F) in Kashmir. Recent claims of temperatures touching 55°C (131°F) in Orissa have been met with some scepticism by the Indian Meteorological Department, largely on the method of recording of such data.

Climatic Areas

Western Himalayas

Srinagar is best from March to October; July to August can be unpleasant; cold and damp in winter. Shimla is higher and therefore colder in winter. Places like Gulmarg, Manali and Pahalgam are usually under several feet of snow (December to March) and temperatures in Ladakh can be extremely cold. The road to Leh is open from June to October.

Northern Plains

Extreme climate, warm inland from April to mid-June, falling to almost freezing at night in winter between November and February. Summers are hot with monsoons between June and September.

Northeast

March to June and September to November are the driest and most pleasant periods. The rest of the year has extremely heavy monsoon rainfall.

Central India

Madhya Pradesh State escapes the very worst of the hot season, but monsoons are heavy between July and September. Temperatures fall at night in winter.

Western India

Summers can be extremely hot with monsoon rainfall between mid June and mid September. November to February is most comfortable, although evenings can be fairly cold.

Southwest

Summer temperatures not as high as Northern India although humidity is extreme. Cooling breezes on coast. Inland, Mysore and Bijapur have pleasant climates with relatively low rainfall. Monsoon rains between late April and July. The most pleasant weather is from November to March.

Southeast

Tamil Nadu experiences a northeast monsoon between October and December and temperatures and humidity are high all year. Hills can be cold in winter.