CBSE Class 9 Answered

Latitude: The Tropic of Cancer passes through India at 23°26′ to the north of the equator. It passes through eight Indian states running from the Rann of Kutch in Gujarat to Mizoram in the east. The Tropic of Cancer divides the country into two halves. The areas in India which lie to the north of the Tropic of Cancer are sub-tropical regions, while areas to the south of the Tropic of Cancer are tropical regions. Temperature remains high throughout the tropical regions.

Altitude: As we go above the sea level, the temperature starts declining. Thus temperature decreases with an increase in altitude. There is a decrease of 1⁰C for every 166 m rise in the height. This is the reason that hill stations are cooler than the plain region. 

Air Pressure and Surface Winds: India lies in the region of the north easterly winds. However, as these winds blow over land, they carry very little moisture and cause no rainfall.

During winters, a high pressure area is created to the north of the Himalayas. Cold winds blow from this region to low pressure areas to the south over the oceans.

During summers, as low pressure areas develop over Central Asia, there is complete reversal of the direction of the winds. Wind moves from a high pressure area over the Southern Indian Ocean. As these winds blow over the warm ocean, they gather moisture and bring rainfall in the country.

The climate of India is also influenced by jet streams. The western cyclonic disturbances in the north and north western parts of the country are brought about by the sub-tropical westerly jet streams.