Notwithstanding predictions of rainfall and thunderstorms over the weekend falling flat, Delhi recorded one of the sultriest days of this summer as it clocked a heat index or “real feel” temperature of 51.3 degrees Celsius (°C) and a peak wet-bulb temperature of 29.77°C, according to the India Meteorological Department (IMD).
The humidity levels were between 35% and 63% on the day, and are set to remain high, experts said, predicting muggy days to continue. They said that the city’s humidity levels were high due to a confluence of weather activity.
“Currently there are southwesterly winds from the Arabian Sea, which are feeding moisture over Pakistan and northwestern India, which are increasing the humidity level. The ‘feels-like’ temperature is high due to this increased humidity, combined with the high temperature. The monsoon is also not close, as, if it were, winds would be approaching from the Bay of Bengal, which we are currently not seeing. So the ‘feels-like’ temperature is likely to remain high over the coming few days,” said Mahesh Palawat, vice president of Skymet Weather.
On the day, Delhi recorded a maximum temperature of 41.3°C, 4.1°C above normal, and a minimum temperature of 30.8°C, 2.9°C above normal.
The heat index—a measurement to indicate what the temperature feels like to the human body when relative humidity is combined with air temperature— remained high throughout the day. It was 46.2°C at 11.30am and 47.8°C at 5.30pm. The higher the humidity, the higher the heat index.
Experts also said that the wet-bulb temperatures of 29.77°C at 2.30pm and 28.09°C at 5.30pm were relatively high.
A wet-bulb temperature of 32°C or higher makes it difficult for even fit and acclimatised people to work outdoors for long. At a value of 35°C — the highest reading on the scale — the human body can no longer regulate temperatures, leading to heat stroke and collapse.
According to the IMD’s forecast, the maximum temperature is likely to remain between 39°C and 41°C until Monday, after which it is expected to start gradually decreasing, to between 33°C and 35°C.
According to the forecast, rainfall is predicted from Monday to Friday, accompanied by thunderstorms and strong winds. A yellow alert for the same has been issued for Tuesday and Wednesday.
The minimum temperature is also expected to follow a similar decline, reaching 21°C to 23°C by Friday.
Palwat said that the upcoming decrease in temperature was due to predicted weather activity. “Although the humidity is likely to remain for a few days, by July 2 or 3, there are chances of scattered rainfall, which should reduce the temperature. Additionally, monsoon is expected after July 4,” he said.