At 41°C, city swelters on hottest April day in 3 years

The mercury on Tuesday continued its upward trajectory in Delhi, as the city recorded a maximum temperature of 41 degrees Celsius (°C) — the warmest April day in three years. Tuesday also qualified as heatwave day in the Capital, and the India Meteorological Department (IMD) has issued a yellow alert for similar conditions for Wednesday as well.

Met officials said Delhi may get partial relief from the heat on Thursday, as a western disturbance influences the region.

The 41°C on Tuesday was recorded at the Safdarjung observatory — the city’s base weather station. This was six notches above normal, and nearly a degree higher than the 40.2°C the previous day. However, other parts of Delhi were even warmer, with Najafgarh recording a high of 41.9°C.

The last time Delhi recorded a higher maximum in April was in 2022, when the city logged a maximum of 43.5°C on April 30. The all-time high for April is 45.6°C, logged on April 29, 1941.

Tuesday’s heatwave conditions led residents to turn to their air-conditioners to beat the heat — reflected in the fact that Delhi’s peak power demand crossed 5,000 MW for the first time this summer season. The Capital’s peak power demand hit 5,029 MW at 3.30 pm, several units higher than the peak of 4,756 MW a day earlier.

“We are seeing heatwave conditions… Clear skies are being seen in northwest India and the winds are dry,” said an IMD official.

According to IMD, a heatwave is when the maximum temperature is above 40°C, while the departure from normal is 4.5°C or more. It is also a heatwave if the maximum is over 45°C in the plains. IMD calls it a “severe heatwave” when the maximum is above 40°C, and the departure is 6.5°C or more above normal.

Met data shows that generally, temperatures cross the 40°C threshold in the second half of April. Last year, this happened on April 26 (40.5°C). In 2023, it was on April 15 (40.5°C), and on April 7 (40°C) in 2022. The earliest it has happened in the last decade was March 30 in 2021, when the maximum was 40.1°C, IMD data showed.

As temperatures increase, the state load despatch centre (SLDC) has forecast Delhi’s peak power demand to hit the 9,000 MW mark this summer for the first time ever.

Delhi’s nights too are getting warmer in the city. The minimum temperature on Tuesday was 22.4°C, two degrees above the seasonal average. It was 20.2°C the previous day and 18.5°C on Sunday.

IMD has forecast heatwave conditions in Delhi on Wednesday as well, with the maximum likely to hover between 39°C and 41°C in most parts of the city, before the mercury slightly dips on Thursday.

“A western disturbance will influence northwest India from Thursday, which will provide marginal relief as cloudiness will return,” the IMD official said.

The minimum too is forecast to rise further, hovering between 22-24°C on Wednesday and Thursday, IMD said.

Separately, Delhi’s pollution levels remained in the “poor” category for a third straight day, with a 24-hour average air quality index (AQI) reading of 243 at 4 pm on Tuesday. It was 261 (poor) a day earlier.

Forecasts by the Centre’s Early Warning System (EWS) for Delhi shows AQI is likely to improve to the “moderate” range on Wednesday as wind speed picks up in the region.