Delhi feels the heat, real feel temp touches 48.5°C

Hindustan Times

19-05-2025

The Capital clocked a hot and humid day as a combination of clear skies and increased moisture led to uncomfortable weather conditions. Although a maximum temperature of 40.8 degrees Celsius (°C) was recorded on the day, which is normal for this time of the year, high relative humidity—ranging from 44% to 74%—gave Delhi a heat index (HI) or 'real feel' temperature of 48.5°C, according to India Meteorological Department (IMD) data.
The high relative humidity translated into increased power consumption in the city too, with the peak power demand crossing the 7,000MW threshold for the first time this season.
Delhi's heat index a day earlier was 43.6°C and this rapid single-day increase led to uncomfortable conditions.
HI is a measurement to indicate what the temperature feels like to the human body when relative humidity is combined with air temperature. The higher the humidity, the higher the heat index.
Delhi's wet bulb temperature, another indicator of thermal discomfort outside, was 28.87°C at the same time. A wet bulb temperature of 32°C or higher makes it difficult for even fit and acclimatised people to work outdoors for long, and at a wet bulb temperature of 35°C—the maximum threshold—humans can no longer regulate body temperatures, leading to heatstroke and potential collapse.
Delhi's peak power demand, meanwhile, was recorded at 7,265MW at 3.29pm on Monday, according to data from the State Load Despatch Centre (SLDC). This was the highest peak power demand in the May 1-19 period in the past four years, data showed. It was 7,174MW in 2024, 5,953MW in 2023 and 7,070MW in 2022. For reference, last year's peak power demand, which was also the all-time peak demand, was 8,656MW, recorded on June 19.
Delhi's power discoms, BSES and Tata Power DDL, both said they were able to meet the increased power demand successfully, without any network constraint or supply disruption.
IMD has forecasted Delhi's maximum temperature to dip, but humidity is expected to remain high, which may give rise to possible light rain and thunderstorms until Saturday. Delhi is expected to record a maximum temperature of 38-40°C until then, albeit with dust-raising gusty winds of up to 50 kilometres per hour.
'There are chances of isolated thunderstorm activity and light rain from Tuesday to Saturday. Such spells are likely on account of high temperature and some moisture incursion,' an IMD official said.
Mahesh Palawat, vice president at Skymet Meteorology, said western disturbances have been recorded in northwest India one after another, which have kept humidity high. 'Western disturbances have existed as a cyclonic circulation and this cyclonic circulation is what is feeding moisture to the region. At the same time, temperature is high and this gives rise to local thunderstorm activity, strong winds and then short but intense spells of rain,' he said.
AQI back to 'poor' again
Delhi's air quality index (AQI) deteriorated to the 'poor' category on Monday, with ozone emerging as the day's prominent pollutant. The 24-hour average AQI was 201 ('poor') at 4pm on Monday, according to the Central Pollution Control Board's daily bulletin. In comparison, the AQI was 179 ('moderate') a day earlier.
The Commission for Air Quality Management (CAQM) in NCR also convened an emergency meeting to discuss whether Stage 1 measures of the Graded Response Action Plan (Grap) were needed, but decided against it, citing an improvement in AQI later in the day.
CAQM said that while the AQI was over 200 at 4pm, it was down to 186 by 7pm. CAQM officials said they will continue to review the situation.
Forecasts by the Centre's Air Quality Early Warning System (EWS) for Delhi show AQI is likely to remain 'moderate' till Thursday.