The minimum temperature in Delhi dropped to 7.5 degrees Celsius on Friday morning, the lowest in November since 2006, according to data from the met department, as experts predicted an early winter for the national capital
On November 29, 2006, the minimum temperature had dropped to 7.3°C, officials said.
Data from the India Meteorological Department (IMD) shows that till November 16, the average minimum temperatures recorded in the city have been two to three degrees below the normal for the season.
Friday’s minimum temperature was five notches below normal for this time of the year.
In November 2019, the lowest temperature was 11.4°C and in the same month the previous year, this was 10.5°C.
According to IMD scientists, the minimum temperature does not usually drop below 10 degrees Celsius in November.
“It’s unusual for minimum temperatures to drop to single digits in mid-November. Winter is setting in early this year. The drop in night temperature is mainly due to a combination of cold winds blowing from the snow-clad western Himalayan region and largely clear skies in Delhi. When there is no cloud cover, the ground cools faster and minimum temperatures stay low,” said Kuldeep Srivastava, head of IMD’s regional weather forecasting centre.
He added that snowfall in the Himalayas, which is an annual phenomenon, has an impact on temperatures across northwest India, but local factors such as absence of cloud cover also play a crucial role.
Delhi this year also saw the coldest October in 58 years with the mean minimum temperatures for the month settling at 17.2°C. The last time it was this cold at night in the national capital was in 1962, when the mean minimum temperature for October was 16.9 degrees Celsius, as per IMD data.
VK Soni of IMD’s environment monitoring research centre, said the minimum temperature is likely to remain around 7-8 degrees Celsius over the next two days. “On November 23, there will be a slight increase in the minimum temperature because of cloud cover in Delhi. Whenever there are clouds, there is a rise in minimum temperature,” he said.
Meanwhile, falling temperatures and continuing stubble fires have kept the air quality in the far-end of the ‘poor’ category, despite strong winds. The average wind speed on Thursday was 15-16kmph, favourable for the dispersion of pollutants.
As per the Central Pollution Control Board’s (CPCB) 4pm bulletin, the average air quality index (AQI) was 296, up from 283 on Thursday.
“The deterioration in air quality is mainly because the wind direction is north-westerly and since some stubble burning activity is still continuing, the smoke is travelling to Delhi and not allowing improvement. However, wind speeds are likely to remain high over the next two days and there may be a slight improvement in air quality. We don’t expect any significant deterioration at least till November 23,” Soni said.
As per the System of Air Quality and Weather Forecasting and Research (Safar), the Union earth science ministry’s air quality forecasting wing, the air quality may touch ‘very poor’ by Friday night, as the winds turn calm during the night. But, it is likely to improve marginally thereafter on November 21-22 with good winds speed expected in the city.
The share of stubble burning to levels of PM2.5 (the most harmful aerosols in Delhi’s air) in the city on Friday reduced to 15% from 20% the previous day, the Safar bulletin stated.
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