Heatwave in North India

In view of heatwave conditions, the India Meteorological Department has issued yellow warning for western Rajasthan, Punjab, Haryana, Delhi, western UP, MP, and Jharkhand.

What are Heat Waves?

• Heat Wave is simply, a continuous spell of abnormally hot weather. Heat wave need not be considered till maximum temperature of a station reaches at least 40º C for Plains and at least 30º C for Hilly regions.
• Criteria for declaring Heat Wave followed by IMD

Situation 1 - When normal maximum temperature of a station is less than or equal to 40º C. Declare Heat Wave if:

• Heat Wave Departure from normal is 5º C to 6º C
• Severe Heat Wave Departure from normal is 7º C or more

Situation 2 - When normal maximum temperature of a station is more than 40º C. Declare Heat Wave if:

• Heat Wave Departure from normal is 4º C to 5º C
• Severe Heat Wave Departure from normal is 6º C or more

Situation 3 - When actual maximum temperature remains 45ºC or more irrespective of normal maximum temperature, heat wave should be declared.

Impact based heat wave warning issue by India Meteorological Department (IMD):

Health impacts of heat wave: