Delhi ‘feels like’ it is 54°C

Delhi faced severe heat on Thursday, with temperatures reaching 43.9°C and a heat index of 54.4°C due to high humidity; a yellow alert is issued for Friday.

The sun showed no mercy on Thursday, but it was the air—heavy, wet, and unmoving—that brought Delhi to a near standstill. For the fourth straight day, isolated parts of the city slipped into heatwave conditions, with Safdarjung, the Capital’s base station, recording a maximum of 43.9°C — four degrees above normal and the highest so far this year.

A white tiger relaxes in a pond at the Delhi zoo as the maximum temperature touched 43.9°C on Thursday. (Sonu Mehta/HT Photo)

While the temperature eclipsed Tuesday’s 43.8°C, it was the suffocating humidity that turned the day unbearable. According to the India Meteorological Department (IMD), Delhi recorded 42.2°C at 2:30pm, but with 39% relative humidity, the Heat Index (HI) touched 53.6°C. By 5:30pm, it soared to 54.4°C — the most punishing so far this season.

In comparison, Delhi’s highest HI on Wednesday was 51.9°C, and the wet bulb temperature — a key indicator of heat stress — was 29.6°C. On Thursday, it hovered between 30.1°C and 30.5°C, inching closer to the 32°C threshold where the human body begins to lose its ability to cool itself.

The IMD defines a heatwave as a maximum temperature exceeding 40°C with a departure of at least 4.5°C above normal, or any instance where the maximum touches 45°C or more in the plains. While most city stations didn’t meet these thresholds, northwest Delhi’s Mungeshpur recorded 45.2°C — the only location to qualify outright. The IMD clarified this was the first validated reading from Mungeshpur after nearly a year, following a sensor replacement. The station had been pulled offline last June after an erroneous 52.9°C reading.

Delhi’s minimum temperature also climbed to 30.7°C — three degrees above normal — compounding night-time discomfort. It was 27.2°C a day earlier.

“Heatwave was recorded in isolated pockets in the city. A heatwave is not likely tomorrow, but it will be hot and humid during the day,” an IMD official said.

Looking ahead, the IMD has issued a yellow alert for Friday. The maximum is expected to ease slightly to 41-43°C, but oppressive humidity will persist. Light rain and gusty winds reaching up to 60 km/h may bring brief relief, especially over the weekend.

Thursday’s torment marked the peak of Delhi’s hottest spell this year — a sharp contrast to May’s rain-soaked calm. That month ended with a record 184.6mm of rain, and not a single heatwave day — a first in recent memory. But June appears determined to make up for the lull.

The southwest monsoon, which progressed swiftly over southern India, has temporarily stalled. While the IMD has not committed to a timeline, Delhi’s normal monsoon onset is June 27.

Meanwhile, Delhi’s air quality remained poor, worsened by the stagnant atmosphere. The average AQI was 195 (moderate) at 4pm, with ozone emerging as the lead pollutant — a pattern typical during extreme heat spells.