(а) Latitude. Tropic of Cancer passes through the middle of India. Therefore, northern half lies in the Temperate Zone and the southern half lies in the Torrid Zone.
The climate of a place is affected by its distance from the equator. Places near the equator are hotter than the places which are away from it.
(b) The Himalayan Mountain Wall acts as a barrier and affects the climate in two ways:
(i) The cold winds from Central Asia are not allowed to enter India, thus saving it from a severely cold climate. (ii) The Himalayas intercept the rain-bearing S.W. Monsoons causing heavy rain in India.
(c) Altitude. Places located on high mountains are cooler as there is a drop of 6°C per km in temperature, e.g., Nainital is cooler than Lucknow in summer.
(d) Distance from the Sea. Places near the sea have a moderate climate while places in the interior have an extreme one, e.g., Chennai and Mumbai have a moderate climate whereas Lucknow and Delhi have an extreme climate.
(e)Varied Relief. The distribution of rainfall depends on the regional or local relief.
(i) Windward side of Western Ghats gets heavy rainfall but the Deccan plateau gets less rainfall as it lies in the rain- shadow area.
(ii) Rajasthan lies in the rain-shadow of the Aravalli Hills and is dry. It does not receive rainfall from the Bay of Bengal Branch of the S.W. monsoons.
(iii) Cherrapunji gets heavy rain as it lies on the windward slopes of Khasi-Garo Hills but Meghalaya lies in the rain-shadow area and gets less rain.
(f) Western Disturbances or Temperate Cyclones. These originate from the Mediterranean Sea and move towards northwest India causing rainfall in the plains and snowfall in the hilly regions. These help in the growth of winter crops like wheat and barley.
(g) Jet Streams. The air currents which blow in the upper layer of the atmosphere and help western disturbances to enter into India.