What’s on Delhi’s summer outlook? More heatwave days, rainfall deficit to continue

According to the rain forecast for April, the Capital will receive below-normal rainfall. Among the nearby areas, isolated parts of Haryana are expected to receive normal to above-normal rainfall, as per the weather office. A majority of Uttar Pradesh is also expected to receive below-normal rainfall. However, isolated parts, mainly on the eastern side of the state, are set to receive above-normal rainfall.

“During April to June hot weather season, an above-normal number of heatwave days are likely to occur over most parts of the north and east peninsula… and plains of northwest India,” reads the IMD’s seasonal outlook.

As per the IMD’s anomaly of heatwave duration (in days) for the April-June duration, the Capital is expected to see an additional two heatwave days while in some parts of the NCR (National Capital Region), the number of extra heatwave days can go up to four.

In April, cities in South Haryana close to Delhi, including Faridabad and Gurgaon, are likely to see a higher number of heatwave days than normal.

In a briefing to reporters, IMD director Mrutyunjay Mohapatra on Monday said, “Both the maximum and minimum temperatures will be above normal in the Indo-Gangetic plains and adjoining areas, which will cause discomfort to people in the coming weeks in April.”

For it to be called a heatwave day in plains, at least two stations for two days in a row should record the maximum temperature at or above 40 degrees Celsius with a departure of 4.5 to 6.4 degrees Celsius from normal.

A temperature analysis for March over recent years shows that the city recorded a higher mean maximum temperature (32.3 degrees Celsius) this year compared to the last two years.

At 15.5 degrees Celsius, the mean minimum temperature was also higher than last year (14.3 degrees Celsius) even as it was lower than that in 2023 (16.2 degrees Celsius).

The city did not see any heatwave days in March. However, unusually above-normal temperatures, touching 40 degrees Celsius, were reported in some stations in the Capital during the month. The city logged two rainy days.

On Monday, the maximum temperature was 35 degrees Celsius, around two degrees above normal, and the minimum temperature at 13.8 degrees Celsius was below normal by four degrees Celsius.

Monthly average AQI best in 5 years

Meanwhile, the monthly average air quality index in the Capital stood at 170 this year, the best in five years, as per data from the Central Pollution Control Board (CPCB). While the average AQI for 2021, 2022, and 2024 stood at 223, 217, and 176, respectively; 2023 recorded the same AQI during the three months as this year.

“The average AQI of Delhi for the January-March 2025 quarter has also been the best during the last five years… This quarter in 2025 did not witness even a single day with an average AQI more than 400,” said the Commission for Air Quality Management in a statement on Monday. From January to March, the average AQI was 231 in contrast to 250 last year, 240 in 2023; 241 in 2022; and 278 in 2021.

The Commission Saturday withdrew Stage I of the Graded Response Action Plan as the AQI improved and was in the ‘moderate’ category. Air quality is forecast to be in the ‘moderate’ category till April 9, as per the Indian Institute of Tropical Meteorology’s air quality forecast system.