The Indian Weather: The Indian sub-continent has a tropical monsoon climate. Monsoons dominate the climate of the sub-continent. Monsoons exercise a unifying influence on the weather conditions of India making it a single meteorological unit. India has a broad unity of monsoon type of climate having the same rhythm of season. The advance and retreat of monsoon divide the weather into different seasons.

(A) Seasons of N.E. Monsoons.

1. The Cold Season. December to February.
2. The Hot Season. March to May.

(B) Season of S.W. Monsoons.

1. The Rainy Season. June to September
2. The Season of Retreating Monsoon. October to November.

1. The Cold Season: The cold season lasts from December to February.
(a) Temperature. The sun is overhead at Tropic of Capricorn. The Indian sub-continent has winter season. January is the coldest month. The southern parts have warm conditions. (20°C) while low temperatures (10°C) are found in N.W. India.

(b) Pressure and Winds. High pressure is developed over N.W. part while a low pressure exists over the Indian Ocean with the result winds blow from land to sea. The out-blowing winds are Westerly in Northern plain and North Easterly over the rest of the country.

Rainfall. The N.E. Monsoons are off-shore winds and are dry. But these winds pick up some moisture crossing Bay of Bengal and give rain to S.E. coast of India. Some cyclones from Mediterranean Sea also bring a small amount of rain (10 to 20 cms.) to Northern plains. Night Frost is common in the N.W. parts.

2. The Hot Season. The hot season lasts from March to May.

(а) Temperature: As the sun’s rays fall vertical over Tropic of Cancer, the temperature begins to rise. The average temperature is above 30 C; the maximum temperature rises to 50°C in Banner (Rajasthan). The daily range of temperature rises in inland areas.

(b) Pressure and Winds: Intense heat results in the development of low pressure over N.W. India and Pakistan. A high pressure exists over Indian Ocean. S.W. Monsoons begin to blow from sea to land. ‘Norwesters’ and ‘Loo’ blow over Northern plains.

(c) Rainfall: Some areas receive convectional rainfall. The west coast also starts receiving rainfall. Most of the country is dry in the pre-Monsoon period.

3. The Rainy Season: The rainy season lasts from June to September.

(а) Temperature: The sun shines vertical over Tropic of Cancer. The temperatures are more than 30°C. With the onset of monsoon, there is a drop in temperature (5° to 10°C) with the result July is not the hottest month.

(b) Pressure and Winds: S.W. Monsoons blow from sea to land with a “burst’ on the West coast. It blows in two currents.

1. The Arabian Sea Current,
2. The Bay of Bengal Current

(c) Rainfall: S.W. Monsoons are rain giver as most of the sub-continent gets rainfall in this season. The Arabian Sea branch gives heavy rainfall on the West Coast, but Deccan plateau lies in rain shadow of Western Ghats. The Bay of Bengal branch gives heavy rainfall in Eastern Himalayas. The rainfall goes on decreasing up the Ganges valley with the decrease in moisture. Rajasthan is practically a desert.

4. The Season of Retreating Monsoon: S.W. Monsoons begin to withdraw from the sub-continent during the first week of October. The sun begins to move towards equator. There is a decrease in temperature. Hot and sticky weather is found. Some tropical cyclones are developed which give heavy rainfall in coastal areas. Cool-weather begins in N.W. India, but the Southern parts have an equable climate.