Delhi’s hottest night in 55 years in a summer without respite
The city’s power demand also surged to a new high of 8,656 megawatts, setting a record for a second consecutive day on Wednesday, said data from local discoms
Tuesday night was Delhi’s hottest in at least 55 years, with a temperature of 35.2°C, data from the India Meteorological Department (IMD) showed, as a scorching, unprecedented summer tightened its debilitating grip on the national capital, squeezing its water supply and sending hundreds of people to hospital with heat-induced illness.
The city’s power demand also surged to a new high of 8,656 megawatts (mw), setting a record for a second consecutive day on Wednesday afternoon, said data from local discoms.
Delhi's power demand at all-time high amid severe heatwave; touches 8,656 MW
IMD data logged from 1969 showed that Tuesday night’s temperature was eight degrees above normal and eclipsed the previous high of 34.9°C on May 23, 1972, even as the weather office forecast that the unrelenting heatwave, now 11 days long, will let up to some extent by Thursday.
To be sure, the weather agency said it was yet to analyse data between 1901 and 1968, and it may well be that Tuesday night was Delhi’s hottest ever recorded.
It was also the city’s sixth straight “warm night” – declared when the maximum temperature is above 40°C and the minimum 4.5°C or more above normal – as the singed earth, baked by the full might of the sun throughout the day, struggled to dissipate heat even hours after sundown.
The maximum temperature at the Safdarjung base station on Wednesday dipped marginally to 43.6°C, five degrees above normal and within IMD’s “heatwave” threshold. It was 44°C on Tuesday. Delhi’s heat index, or “real-feel” temperature, however, was unchanged at 51°C.
Delhi’s maximum temperature has been over 40°C for 37 consecutive days now.
And if all of this wasn’t enough, Delhi’s air quality tumbled on Wednesday as well, as strong, dusty winds that have blown in from the western deserts for most of the month settled down and kept local pollutants suspended in the air. The air quality index (AQI) worsened from 196 (moderate) on Tuesday to 306 (very poor) on Wednesday.
The humidity oscillated between 31% and 47% throughout the day.
According to the weather office, an incoming western disturbance on Thursday may push the maximum temperature down to 42°C and the minimum to 33°C.
The early effects of this western disturbance, however, likely worsened the heat on Tuesday night, said weather officials.
“We were already recording high minimum temperatures, but the approaching western disturbance added more moisture and cloud cover late on Tuesday and in the early hours of Wednesday. High clouds keep heat loss low,” said an IMD official.
The official added that IMD will assess detailed weather records before 1969 towards the end of the month.
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“Normally for extreme weather, we look at 30-year-old data. For Safdarjung, data between 1969 and 2024, which was available, was analysed. We will assess older data at the end of the month,” said the official.
Mahesh Palawat, vice-president of Skymet, a private weather forecaster, said such soaring minimums were unprecedented.
“We do have high minimums in May and June, but not to this extent,” said Palawat.
“We are currently seeing strong westerly winds blowing even at night-time and for the last few days, are seeing a double impact of cloudiness from a western disturbance. From July onwards, the minimum starts to dip again as we see monsoon rains in Delhi,” he said.
The difference between the maximum and minimum temperatures was just 8.4°C at Safdarjung on Wednesday and has been shrinking for the past couple of days, with the night providing little succour from the day.
This gap between maximum and minimum temperature was 10.2°C on Tuesday and 12.2°C on Monday. Around this time of the year, the gap stretches to around 15°C, with the minimum dipping to 30°C on most nights in May and June, the hottest summer months.
“Delhi has not recorded any significant rain since May. The surface is heating up and dry, westerly winds are sweeping through even at night, not allowing this heat to be lost into the atmosphere,” he added.
Delhi’s wet-bulb temperature, another indicator of comfort levels outside, was between 27.5°C and 28.5°C on Wednesday, up from 27.1°C-27.5°C a day earlier.
A higher wet bulb temperature makes it difficult for people to remain outside, let alone work outdoors. A wet-bulb of 32°C or higher makes it difficult for even fit and acclimatised people to work outdoors for long and at a wet-bulb temperature of 35°C — the maximum threshold — humans can no longer regulate body temperatures, leading to heatstrokes and potential collapse.
HT on June 8 reported that this is Delhi’s driest start to the year since 2018, with only 44.7mm of rain recorded at Safdarjung between the first five months of this year. This is only 42% of the long-period average of 104.8mm, which Delhi’s base observatory receives in the first five months of the year. The last time Delhi received less rainfall at the start of the year was 43.5mm in 2018.
IMD sets date for monsoon onset in Delhi-NCR as residents reel under heatwave
Vishwas Chitale, senior programme lead, Council on Energy, Environment and Water (CEEW) warned that the climate crisis would precipitate more such unfettered heatwaves.
These high nighttime temperatures pose serious health concerns, as they prevent the earth from cooling down after the daytime heat. It is becoming increasingly clear that due to climate change, boiling summers are the new normal and that we need year-round preparedness to be more proactive than reactive in dealing with heatwaves,” Chitale said.
