Delhi Heatwave Alert: Mercury Soars to 40.1°C, IMD Issues Yellow Warning
After a brief respite from rain, Delhi's temperatures have surged once again, with the maximum temperature reaching 40.1 degrees Celsius on Sunday at the Safdarjung base station. This reading is three degrees above the normal level for this time of year, signaling a return to intense heat conditions.
IMD Issues First Heatwave Alert of the Season
The India Meteorological Department (IMD) has issued a yellow alert for heatwave conditions in isolated areas from Wednesday to Friday. This marks the first such warning of the current season, with temperatures expected to climb as high as 43°C during this period.
On Friday, Delhi experienced its highest maximum temperature of the season at 41°C. However, the weather shifted dramatically in the evening, bringing intense rain, lightning, and gusty winds that provided temporary relief. Saturday saw temperatures dip below 40°C, but this cooling effect proved short-lived.
Hottest Stations and Weather Patterns
The Ridge observatory in north Delhi recorded the highest temperature on Sunday at 41.8°C, followed by Mungeshpur in northwest Delhi at 41°C. Meteorological officials attribute the rising mercury to consistently hot north-westerly winds and extended hours of sunshine, conditions expected to affect Delhi, Punjab, Haryana, and north Rajasthan in the coming days.
Forecasts predict maximum temperatures of 41 to 42°C on Monday and Tuesday, potentially increasing to 41-43°C from Wednesday through Friday.
Expert Analysis and Western Disturbances
Krishna Mishra, a scientist at IMD, explained that a western disturbance which caused rain in the Himalayan region passed on Sunday. Another disturbance is anticipated to impact the Himalayas starting April 23, but its weak nature means Delhi is unlikely to experience any significant relief over the next seven days.
Mishra added that certain stations in Delhi might encounter heatwave conditions as early as Monday, with isolated areas likely to face heatwaves from April 22 onward.
Health Concerns and Heatwave Criteria
The Met department has noted that while current heat levels remain tolerable for most people, they pose moderate health risks to vulnerable populations. This includes infants and elderly individuals suffering from chronic illnesses who may experience heightened health concerns during this period.
IMD defines a heatwave day when the maximum temperature reaches at least 40°C and exceeds the normal temperature by 4.5°C or more. Alternatively, a heatwave is declared if the maximum temperature touches 45°C.
Historical Context and Current Conditions
While no heatwave days were recorded in April this year, nor in April 2024 or 2023, three such days occurred in the second week of April 2025. In contrast, April 2022 witnessed Delhi's most intense heatwave spell in recent years, with 11 heatwave days recorded.
Sunday's minimum temperature settled at 21.7°C, near normal for this season, with forecasts indicating a rise to 24°C by Thursday.
Air Quality Deterioration
Meanwhile, Delhi's air quality has worsened, entering the poor range with an Air Quality Index (AQI) of 258. Following Friday evening's rain, the AQI improved to the moderate category at 152 on Saturday. However, the Air Quality Early Warning System for Delhi forecasts that poor air quality conditions will persist at least until Wednesday.
