India’s 2024 general election season may be marked by hotter-than-usual days.

Most parts of the country are likely to experience heatwave durations six days to 14 days longer than average, the India Meteorological Department (IMD) said on Friday, releasing its seasonal outlook for the weather from March to May.

The IMD’s forecast suggests extra heatwave days across vast swathes of central, eastern, northern and western India and parts of southern India (see map). Extra heatwave days are unlikely in the northeast, the western Himalayan region, the southwest peninsula and the west coast.

The probability forecast also indicates that above-normal maximum temperatures are most likely over most parts of the country from March to May, except over some isolated areas of northwest, northeast, central and peninsular India where below-maximum temperatures are most likely.

“The heatwaves are predicted to occur in areas where they usually occur, but some places are likely to have extra days of heatwaves,” said the IMD’s director general Mrutyunjaya Mohapatra.

Parts of Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Telangana, and Uttar Pradesh are predicted to experience heatwave durations lasting 9 to 15 days longer than usual, according to the IMD forecast.

The monthly maximum temperatures in March 2024 will most likely be above normal over parts of the southern peninsular region, northeast and west central India and northwest India and normal to below normal in east and east-central India.

A “most likely” forecast from the IMD implies a probability of 75 per cent or higher.

Heatwaves in India typically last between four and eight days, the IMD had said earlier based on an analysis of weather data between 1961 and 2020. But heatwave durations have exceeded eight days in some parts of central and northwestern India, Odisha and coastal Andhra Pradesh. A 2019 heatwave in northwest India lasted 14 days — May 29 to June 11.

The IMD declares a heatwave when the normal maximum temperature at a site ranges between 4 degrees Celsius and 5 degrees Celsius above the normal for that site or when the maximum temperature remains 45 degrees Celsius or higher irrespective of the normal maximum temperature.