New Delhi: The city continued to suffer an intense and prolonged heat wave on Thursday, which now also suffers from thermal stress at night. The city recorded the first “warm night” of the season, a condition that will likely persist in the coming days.The minimum temperature at the city’s base station, Safdarjung, was set at 31.9°C (5.2 degrees above normal), making it the warmest May night in Delhi in 14 years, according to IMD data. A higher minimum temperature for May (34.2°C) was recorded on May 27, 2012. Delhi had last witnessed warm night conditions on April 9 and 10, 2025.The heat wave that began on Monday shows no signs of letting up. The India Meteorological Department (IMD) has extended its heat wave alert until next Wednesday. “Heat wave conditions were observed at some places over Delhi on Thursday, making it the fourth consecutive day. Delhi also experienced warm night conditions. In this likely scenario where dry northwesterly to western lower troposphere winds prevail in the absence of strong western disturbance, heat wave conditions will continue to affect Delhi till May 27,” an IMD official said.A “warm night” is when the maximum temperature exceeds 40°C in the plains and the minimum that day is 4.5 degrees or more above normal. A “heat wave” is declared when the maximum temperature exceeds 40°C and is also at least 4.5 degrees above normal. Daytime conditions are also classified as a heat wave if temperatures exceed 45°C in the plains. A “severe heat wave” is declared when the maximum temperature exceeds 40°C and is 6.5 degrees or more higher than normal.The maximum temperature in Safdarjung reached 43.6°C, 3.4 degrees above normal, while Ridge recorded a scorching 45.3°C.“There is a lack of impact of western disturbances on the plains of north-west India, though Jammu and Kashmir experienced consistent western disturbances and fairly widespread rainfall. But as the western disturbances are not of sufficient amplitude, they are not likely to affect north-west India. Therefore, the heat wave will continue to impact the city. Red to orange alerts have been issued for Punjab, Haryana, Delhi, north Rajashtan and MP and south UP,” said IMD scientist Krishna Mishra.An orange alert for heatwave conditions has been issued for Delhi until May 27, while warm night conditions are expected again on Friday.Last May, Delhi’s highest maximum temperature was 42.3°C and the city recorded no heat wave days. By contrast, 2024 saw six consecutive days of heat waves, with the mercury peaking at 46.8°C on May 30. On the same day, stations like Narela and Mungeshpur exceeded 49°C.Delhi’s air quality once again fell into the poor zone. The ICA stood at 209 at 4:00 p.m. on Thursday, compared to 168 on Wednesday.
