Delhi gets light rain, but high humidity keeps relief at bay

Parts of the Capital received light rainfall on Sunday, making for another wet day, but prevailing maximum humidity level of 73% ensured it was a sultry day despite the maximum temperature remaining below the 40°C mark, at 39.8°C, for a second day in a row.

Delhi rain: Has monsoon arrived early in Capital, or a temporary relief?

The maximum temperature was a degree above normal, according to the India Meteorological Department (IMD). It was 39.4°C on Saturday and 40.4°C on Friday.

Despite the relatively lower maximum temperature, high humidity made it an uncomfortable day to be out in the open, with the heat index (HI) or “real feel” of temperature recorded at 53°C, the IMD said in its daily weather bulletin, forecasting no heatwave conditions in Delhi for the remainder of the month.

Delhi’s wet-bulb temperature, another indicator of the comfort level outside, was recorded at 30°C on Sunday at 2.30pm, the highest so far this year. It was 28.4°C at the same time on Saturday and 26.6°C on Friday.

The higher the wet bulb temperature, the more difficult it gets to stay outside and work. 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 heatstrokes and potential collapse.

According to the IMD, Delhi is now likely to see drizzle to light rain till June 29, making for a wet end to the month, marked by pre-monsoon showers, with no heatwave conditions expected. The IMD classifies a heatwave day as one when the maximum is over 40°C and 4.5 degrees or more above normal.

“Parts of Delhi-NCR will see light rain now till the end of the month. This will keep maximum temperature in check, but the humidity will be high,” an IMD official said.

On Saturday, Delhi’s maximum temperature dipped below 40°C for the first time in 40 days. This was Delhi’s longest streak of 40°C or higher days since 1951, when a streak of 32 days was recorded.

According to IMD data, the Safdarjung weather station recorded 0.6mm of rainfall between 8.30am and 5.30pm. During this period, 6.9mm of rainfall was recorded at the Palam station, “trace” rain at Lodhi Road station, 0.8mm of rain at the Ridge station and 1.2mm at the Ayanagar station.

Delhi’s minimum temperature was 29.6°C on Sunday, two degrees above normal. It was 28.6°C on Saturday. The minimum temperature is likely to hover between 29°C and 31°C till the end of the month, while the maximum will oscillate between 39 and 42°C, the IMD said.

Delhi recorded three heatwave spells this summer, lasting a total of 27 days, where at least one weather station recorded a heatwave. Of these, Safdarjung, representative of Delhi’s weather, recorded a heatwave on 14 days, which was the highest for Delhi in at least 13 years. The previous highest, of 13 heatwave days, at Safdarjung was recorded in 2022.

Heatwave gives way to high humidity in Delhi

The first heatwave spell in Delhi lasted four days, from May 17 to May 20. From May 21, moist easterly winds led to a drop in temperature and heatwave conditions abating. A second spell — the harshest of the three so far — lasted for 12 days, between May 25 and June 5, with the maximum temperature touching a high of 46.8°C on May 29. The third spell began on June 9 and lasted till June 20, with its end marked by a return of rain to most parts of Delhi on June 21.