Mercury crosses 40-degree mark before rain lashes Delhi

The India Meteorological Department (IMD) attributed the rapid change in weather to a combination of factors — a western disturbance in northwest India and an induced cyclonic circulation over west Rajasthan that brought moisture to Delhi and the National Capital Region (NCR).

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April 26 is the latest the mercury has passed the 40°C threshold in a decade. According to IMD data, Delhi passed this mark on April 29 in 2014.

Dark clouds began shrouding a clear sky that marked a hot day a little after 5pm. According to airport officials, two flights were diverted till around 8pm due to bad weather after the city recorded short but intense spells of rain. "Both were diverted due to Jaipur," said an airport official, adding that more diversions may happen due to strong surface winds later in the night.

The maximum temperature on Friday was recorded at 40.5°C at Safdarjung, representative of Delhi's weather. This was a degree above normal and a degree above Thursday's maximum of 39.4°C, which was the previous highest this season.

Though no rain was recorded till 5.30pm at any weather station, the Safdarjung observatory recorded 2.6mm of rainfall between 5.30pm and 8.30pm, while Palam received 3.2mm in these three hours.

During the day, temperatures shot up due to clear skies touching the 42°C mark in isolated pockets around the city. At Mungeshpur in northwest Delhi, it went up to 42.2°C — the highest maximum recorded at any weather station in Delhi so far this year. At Pusa and Pitampura, it was 42°C each.

Delhi usually surpasses the 40-degree mark in the second and third weeks of April. Last year, the maximum touched 40.5°C on April 15. In 2022, it breached the 40-degree mark on April 7 (40°C) and in 2021, on April 13 (40.2°C), according to IMD data. Data showed that the last time the mercury took this long to breach the mark was in 2014, on April 29 (40°C).

The cyclonic circulation led to gusty winds of up to 50km/hour first, followed by rain. "Both these weather systems brought strong dust-raising winds. At Palam, wind speed touched around 50km/hour and at Safdarjung, it was 25km/hour. It may have been even higher at other places," said Kuldeep Srivastava, scientist at IMD, adding that the thunderclouds moved from west to east Delhi.

"Strong winds were reported after 5pm and rain was recorded in several places after 5.30pm. The spells were particularly intense in north and south Delhi," Srivastava said. IMD's weather stations did not record any rainfall between 8.30am and 5.30pm on Friday.

Met officials said a drizzle may hit through the city on Saturday too, as the impact of these phenomena may remain — with gusty winds of 25-35 km/hour likely. The maximum is likely to dip marginally and hover around 39°C.

Meanwhile, the minimum temperature recorded a low of 21.6°C, which was two degrees below normal. It was 20°C on Thursday and is forecast to hover around 24°C on Saturday.

Delhi recorded a 24-hour average air quality index reading of 195 at 4pm, which was "moderate". It was 199 (moderate) at the same time on Thursday.