India experienced one of its hottest years in 2024, but 2025 may surpass it. With heatwave conditions setting in as early as April, the Indian Meteorological Department (IMD) has already issued red alerts in several states. The rising temperatures are being linked to heat trapped due to the warming of sea water, a trend that could make this year one of the hottest on record.
According to the IMD, Gujarat is on red alert from April 6 to 10, with severe heatwave conditions expected in the Saurashtra and Kutch regions on April 6 and 7. Rajasthan is under an orange alert for the same period, where some areas are likely to face severe heatwave spells between April 7 and 9. Yellow alerts have also been issued for Himachal Pradesh, Haryana, Chandigarh, Punjab, Delhi, western Uttar Pradesh, and Madhya Pradesh in the coming days.
With heatwaves starting in early April, concerns are growing over what May and June may bring. The IMD has warned that the number of heatwave days in northwest India—covering Haryana, Punjab, Rajasthan, Himachal Pradesh, Jammu and Kashmir, Uttarakhand, and Delhi—could double this year. Typically, heatwaves last 5 to 6 days, but this summer may see extended spells of 10 to 12 days. If this trend continues, 2025 could become the hottest year ever recorded in India, with temperatures rising 5°C or more above the seasonal average.
A heatwave is defined by the IMD as a period when the temperature in plains exceeds 40°C, in coastal areas exceeds 37°C, and in hilly regions crosses 30°C. A deviation of 4.5°C above the normal constitutes a heatwave, while an increase of 6.4°C or more is classified as a severe heatwave. According to the World Meteorological Organization (WMO), a heatwave occurs when the maximum temperature of an area remains at least 5°C above average for five or more consecutive days.
In recent years, India has been experiencing more frequent and longer-lasting heatwaves. For instance, eastern Rajasthan faced 23 heatwave days in 2024, while western Rajasthan saw 29. Uttar Pradesh was hit hardest, enduring 32 heatwave days. This marks a significant rise from the historical average of 8 to 12 heatwave days in states like Rajasthan and UP.
The IMD has identified 13 states as highly vulnerable to heatwaves. These include Rajasthan, Punjab, Haryana, Chandigarh, Delhi, West Madhya Pradesh, Uttar Pradesh, Chhattisgarh, Odisha, Vidarbha, coastal Andhra Pradesh, Telangana, and parts of Gangetic West Bengal. These regions lie within the Core Heatwave Zone (CHZ), which typically experiences extreme temperatures from March to June, and sometimes even in July. In 2024, records were already broken in April.
This year, the IMD predicts a higher-than-normal number of heatwave days across most of North, Central, and East India. The only exceptions are expected to be the far southern states, parts of the Northeast, Jammu and Kashmir, and Himachal Pradesh.
Scientific studies confirm that heatwaves in India are becoming more intense and frequent. Research from the Indian Institute of Tropical Meteorology in Pune indicates that since 2000, heatwave days have increased by three per decade in many parts of the country. The impact is far-reaching, affecting public health, agriculture, and entire ecosystems. In 2024 alone, India recorded 554 heatwave days nationwide, making it the hottest year on record. By comparison, 2023 had 230 heatwave days.
With early signs pointing to a prolonged and more intense summer, 2025 could see heat levels and records that surpass anything experienced so far.