Why is May the Hottest Month in India Despite the Summer Solstice in June?

The month of May, known as Vaisakha, is often associated with extreme heat in India, even though the summer solstice - the longest day of the year - occurs in June. This article delves into the factors contributing to this phenomenon, exploring both scientific and cultural perspectives.

The Role of Summer Solstice and Seasonal Heating

Despite the summer solstice falling on June 21st, May remains the hottest month in India.

Lag of Seasonal Heating: The Earth’s surface continues to absorb heat even after the longest day of the year, known as the summer solstice. This phenomenon, known as seasonal lag, results in the maximum temperature often being reached a few weeks after the solstice, as the land and atmosphere take time to warm up fully. Intense Solar Radiation: During May, India experiences high solar radiation due to its geographical location. The sun's direct overhead position in many parts of the country increases surface heating, contributing to rising temperatures.

Influence of Weather Patterns

May also marks a period of pre-monsoon conditions in India, with hot and dry winds blowing from the Thar Desert, leading to further increases in temperatures, particularly in northern and central regions.

Reduced cloud cover in May allows more sunlight to reach the ground, exacerbating the heat. As the monsoon approaches in June, cloud cover typically increases, which helps in moderating temperatures.

Additionally, humidity levels can rise significantly in coastal regions, contributing to a heightened sensation of heat even when actual temperatures are not at their peak.

Scientific Explanation and Monsoon Impact

From a scientific standpoint, the land tends to get hotter than the sea. Warm air rises, and cool air from the sea blows in, bringing with it monsoon clouds. This explains the systematic monsoon patterns that occur with relatively little variation each year. This year, the monsoon season began on June 6 at Kerala.

Low Pressure Regions: In the spring season, high temperature creates low pressure regions on the mainland, initiating the monsoon winds. Cooling Effect: As monsoon winds blow over the mainland, they cause rainfall, leading to the natural cooling of the land. The clouds also block out solar radiation, further aiding in the temperature drop.

Without the monsoon, temperatures in the Indian subcontinent would be even higher. The absence of monsoon rains in June could result in temperatures surpassing those of May.

Religious Significance

From a cultural perspective, May is associated with the Hindu festivals of Lord Kartik, the Fire God, and Maha Vishnu. These religious celebrations contribute to a perception of extreme heat.

Vaisakha (May): Devoted to Lord Kartik and Maha Vishnu, Vaisakha is considered a favorable month in Hindu religion, which is often perceived as bringing extreme hot conditions.