Rising heatwave days push last year’s annual mean temperature to a 24-year high

The warming trend was particularly stark during the winter and monsoon seasons. Temperatures during January and February averaged 13.5°, nearly a degree higher than usual. Similarly, during the June–September period, the average temperature rose to 24.63°.

Heatwave Days Rise

The effects of rising temperatures were reflected in the sharp increase in heatwave events. India recorded 200 heatwave days in 2024, up significantly from 111 days seen in the previous year. This is the highest number of heatwave days since 2010, during which 278 such days were reported.

Although coldwave days also increased - 40 days in 2024 from 33 a year ago - they remained below the long-term average of 70 days.

A heatwave day is defined as one where temperatures exceed 40° in plains, or there is a departure of more than 4.5° from normal. A coldwave is typically recorded when minimum temperatures fall below 4° or are at least 4.5° below normal.

Over the last 20 years, India has witnessed a total of 130 heatwave days.

Climate Takes a Toll

The rising frequency of extreme temperatures is also translating into higher fatalities. Heatwaves accounted for nearly 10 percent of all weather-related deaths in India, while exposure to cold accounted for 11 percent.

The nation recorded the highest number of climate-related fatalities in 11 years in FY25, with deaths rising 17.7 percent compared to the previous year, underscoring the urgent need for climate resilience and adaptive infrastructure.