Heat Wave Map: India's Summer of Extremes Visualized

This choropleth map illustrates what a brutal summer India is experiencing this year. 

Source - Hindustan Times

14 out of 36 regions in the country have baked through over 15 heat wave days between March 1 and June 9 as per data from the India Meteorological Department (IMD). 

Since normal temperatures vary across India, the criteria for declaring a heat wave also differs.  

Generally, heat waves are declared when temperatures on the plains exceed 40°C, exceeding 37°C in coastal areas, and exceeding 30°C in the hills.  There's also a deviation factor involved, where temperatures must be 4.5 to 6.4 degrees Celsius above the average maximum for at least two consecutive days. 

If the deviation is even higher (over 6.4 degrees Celsius), it's classified as a severe heat wave.

The impact of these heat waves is further aggravated by factors like high humidity, high wind speed, and the duration of the events.