New Delhi has experienced a relatively mild heat index in recent days, with temperatures staying below 40°C, though the humidity continues to make the heat feel more oppressive.
For the past three days, the heat index in the city has not surpassed 40°C, and according to the India Meteorological Department (IMD), this trend is expected to continue for the next 24 hours. The IMD began monitoring and sharing heat index data this year, offering a more comprehensive view of how the combination of temperature and humidity affects human comfort. On Monday, the maximum temperature recorded at Safdarjung, Delhi’s base station, was 35°C, which is slightly above the seasonal average. However, it was the varying levels of humidity—ranging from 16% to 70%—that caused the discomfort. The heat index, which factors in both temperature and humidity, remained under 40°C, which was a relief given the sweltering conditions experienced in other parts of India in recent weeks.
The concept of the heat index goes beyond just the air temperature. It measures how hot it feels to the human body, considering the effects of humidity. When humidity is high, sweat cannot evaporate efficiently, leading to an enhanced feeling of warmth, even if the actual temperature is lower. With the increasing frequency of heatwaves across the country, understanding the heat index has become crucial for public health and safety.
This marks the second consecutive year the IMD has implemented this measurement system in New Delhi, as part of an effort to issue more accurate and timely warnings about heat-related discomfort. In previous years, heatwave forecasts were issued solely based on temperature readings and their departure from the normal range. The heat index system allows authorities to issue more nuanced warnings, addressing both the heat and the humidity, which together can have far-reaching consequences on health and well-being.
Though the heat index remains below the danger zone for now, experts warn that the coming months will likely see temperatures and humidity levels rise. Last year, the heat index in Delhi remained under 40°C throughout April but soared to a stifling 55.4°C on May 22, when the temperature hit 43.4°C. As the monsoon season approaches, the combination of rising temperatures and increasing moisture in the air will drive the heat index to new extremes.
In the coming weeks, the IMD will continue to track and report the heat index, offering a more accurate reflection of how heat and humidity are impacting the city. The department also warns that the conditions may lead to heatwaves later in the season, especially when temperatures exceed 45°C, creating the potential for severe public health challenges. However, no heatwave conditions are expected in New Delhi over the next week.
For residents of the city, the change in how heatwaves and extreme temperatures are monitored could offer some level of preparedness. With the IMD now factoring in the heat index, citizens will have a clearer understanding of how weather conditions are directly affecting their comfort and health, empowering them to take precautionary measures. As the global conversation on climate change intensifies, the ability to track and manage heat-related risks in urban spaces is becoming more critical in building sustainable and resilient cities.
