In recent years, temperatures have risen and heat waves have occurred in several parts of the country.
Global warming, which is linked to an increase in greenhouse gases such as carbon dioxide and methane in the atmosphere, is one of the reasons for the rise in heat waves.
The months of April, May, and June sees the highest increase in maximum temperatures as well as Heat Waves, in India.
Hot Day
When the maximum temperature is 40°C or higher and the minimum temperature is 4.5°C or higher than normal, it is considered a Hot Day.
Heat Wave
The India Meteorological Department (IMD) tracks heat waves using data from surface observatories. Heat Waves are also tracked using a variety of numerical weather prediction models.
When the actual Tmax of a station hits 40°C for plains and 30°C for hilly regions, it is declared as a heat wave. Temperatures are considered as heat wave when the Tmax reaches 40°C for coastal locations and 45°C for other locations.
The severity of a heat wave is determined by the following criteria:
When the normal Tmax is less than or equal to 40°C and the ActualTmax is higher than the Normal Tmax.
When the normal Tmax exceeds 40°C and ActualTmax exceeds the normal Tmax