New Delhi: Summer, which begins on April 1, and goes on till June 30, will be hotter, with more so-called heatwave days in many states, the India Meteorological Department (IMD) said in its summer forecast.
The weather office’s summer forecast is followed only a little less closely than its monsoon forecast; the intensity and length of the summer has a bearing on lives and livelihoods.
The forecast of higher-than-normal temperatures was not surprising, given that every month since April 2024 has seen a record in terms of heat in at least some parts of the country, although it comes in the context of a particularly benign (albeit, dry) March.
Above normal day and night temperatures are likely over most parts of the country along with above normal heatwave days especially over northwest and east India, IMD said in its forecast on Monday.
Normally there are four to seven heat wave days between April and June but this time there could be between six and 10. “Up to 10 heat wave days or even more can be expected, especially over east India,” said M Mohapatra, director general, IMD.
IMD declares a heat wave when the temperature touches or exceeds 45 degrees Celsius (if it touches or exceeds 47, IMD declares a severe heat wave), or if the maximum temperature touches 40 degrees Celsius in the plains, 30 degrees in the hills, and 37 degrees Celsius in the coast, and is higher than normal by between 4.5 degrees Celsius and 6.4 degrees (if the deviation is higher than that, IMD declares a severe heat wave).
IMD’s forecast said that between April and June, above-normal maximum temperatures are most likely over most parts of the country, except some parts of west peninsular India and isolated regions of east-central and east India where normal maximum temperatures are most likely. During the season, above-normal minimum temperatures are also likely over most parts of the country except some isolated regions of extreme northwest India where normal minimum temperatures are likely, it warned. In effect, get ready for not just hot days, but also warm nights.
That’s going to be the trend in April in isolation too, the weather agency said.
In April, above-normal maximum temperatures are likely over most parts of the country except some parts of extreme south peninsular India and northwest India, where normal maximum temperatures are most likely. Above-normal minimum temperatures are most likely over most parts of India, except some isolated pockets over northwest and northeast India where normal to below-normal minimum temperatures are likely during April 2025.
In addition, April could see more heat wave days, Mohapatra added: up from between one and three to between three and six.
“During heatwaves, elevated temperatures pose significant risks, especially for vulnerable populations like the elderly, children, and those with pre-existing health conditions, who are more susceptible to heat-related illnesses such as heat exhaustion and heatstroke. Additionally, prolonged periods of extreme heat can lead to dehydration and strain infrastructure such as power grids and transportation systems. To address these challenges, anticipatory actions as per guidelines of National and State Disaster Management Authorities and heat action plans may be taken. This includes providing access to cooling centres, issuing heat advisories, and implementing strategies to alleviate urban heat island effects in affected areas etc. among others,” IMD advised.
But there will be some respite in the form of rain if IMD’s forecast is to be believed.
Normal rainfall (88-112% of long period average) is expected in April over the country. Normal to above-normal rainfall is likely over many parts of northwest India, peninsular India, northeast India, and some parts of west central India. Below normal rainfall is likely over remaining parts of the country.
That will provide some relief after a dry March that saw a 32.6% rain deficiency over the country with 41.3% deficiency over northwest India; 38.6% deficiency over east and northeast India; 39.3% deficiency over central India and 33.6% excess over south peninsular India.
Currently, the El Niño-Southern Oscillation (ENSO) condition is transitioning from weak La Niña condition to an ENSO-neutral state with above-average SSTs in the eastern and far western Pacific Ocean and below-average SSTs in the central Pacific Ocean. The latest forecast indicates that neutral ENSO conditions are likely to continue in the upcoming season. Indian Ocean Dipole is also likely to be neutral during summer and monsoon.
“We can say that ENSO neutral conditions are likely during summer and monsoon. A preliminary monsoon forecast will be issued in mid-April,” Mohapatra said.
La Nina refers to the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, such as winds, pressure and rainfall. El Nino is just the opposite, it represents the warm phase of the El Nino/Southern Oscillation (ENSO) cycle.
In India, an El Nino is associated with a harsher summer and weaker monsoon. La Nina, meanwhile, is associated with a strong monsoon, above average rains and colder winters.
IOD is the difference between the temperature of the ocean in two parts — in the Arabian Sea on the west and the Bay of Bengal in the east. A neutral IOD doesn’t affect the monsoon, but a negative one is bad news for the monsoon.
“Global warming is leading to higher temperatures globally including in India. Regional features such as fewer than normal western disturbances is also adding to this. In March we usually see fout to five WDs, this time there were only 2 active WDs which led to lower rainfall,” explained Mohapatra.