9.5°C: Mercury hits season’s lowest in Delhi, capping warmer November
Delhi's minimum temperature dropped below 10°C for the first time this season, marking an unusually warm start to winter amid high pollution levels.
The minimum temperature in Delhi fell below 10°C for the first time this season on Friday, the latest that the mercury has taken to tip into the single digits in five years, in what has so far been an unusually warm start to winter, where pollution levels have also been well above average.
Safdarjung weather station, which is considered representative of Delhi’s weather, logged a minimum temperature of 9.5°C on Friday morning, a degree below normal. However, the mercury last dipped below 10°C this late only in 2019, shows data from the India Meteorological Department (IMD).
Last year, the city’s temperature fell into the single digits on November 23 (9.2°C). In 2022, this happened on November 18 (9.6°C), in 2021 on November 17 (9.6°C), in 2020 on November 19 (9.4°C).
In 2019, the temperature dropped below 10°C on December 1, when the minimum fell to 9.4°C.
“The dip in minimum temperatures over the last few days is mainly down to clear skies at night,” said RK Jenamani, a scientist at IMD.
Days and nights this November have generally been warmer than normal, showed Met department data. The average minimum temperature this month has been the highest since 2019 and the average maximum has been the highest since 2016.
The average monthly minimum temperature this November has been 14.9°C, significantly higher than the long-period average of 13°C and the warmest since 15°C in 2019.
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Meanwhile, the maximum temperature this month has averaged 29.5°C — 1.1°C above the LPA. This is the highest average monthly temperature for the capital in November since 2016, when it was 29.6°C, data showed. The maximum on Friday was 26.4°C.
IMD officials said the mercury was nearly 4-5°C above normal in the first two weeks of November, further skewing the average.
“We have not seen any sufficient rain in the plains, or adequate snow in the higher reaches as strong and active western disturbance have been absent. There was significant snowfall around November 13, after which a dense fog blanketed northwest India. But as the fog has gradually reduced, temperatures have again become normal or gone above normal,” said Jenamani.
“Until we see a strong western disturbance, snowfall and dense fog is unlikely,” he added.
Weather experts also pointed out that October was far warmer than normal as well.
Delhi recorded its warmest October this year since 1951, with both days and nights on an average nearly 2°C higher than normal. The average monthly maximum and minimum temperature this October was 35.1°C and 21.2°C, respectively, the highest since 36.2°C and 22.3°C, respectively in 1951.
Long-period data shows that the minimum usually dips below 10°C in November. However, this happened much later in 2019 (December 1), 2018 (December 2) and all the way on December 13 in 2015, when it fell down to 7°C.
Last November, the minimum fell to a low of 9.2°C (on November 23). It was 7.3°C in 2022 (November 29), 9.2°C in 2021 (November 24) and 6.3°C in 2020 (November 23).
Temperatures are likely to spike again marginally over the weekend before receding once again from Monday, predicted the weather office.
A western disturbance is likely to influence northwest India from Saturday and could push the minimum up by 1-2°C over the weekend as winds slow down. However, a subsequent dip in temperature is likely from Monday, with snowfall likely in the higher reaches, said Met officials.
He said with moisture content also low, dense fog has become shallow over the northern plains these last 10 days.
The Met’s forecast for Saturday shows that the minimum should hover around 10°C. The maximum will be around 26°C.
November also records its second highest average AQI
With rain missing and meteorological conditions mostly unfavourable since November 13, Delhi’s average air quality index (AQI) this month has been 375 – the second highest in the month behind 376 in 2021, showed data from the Central Pollution Control Board (CPCB).
This included eight “severe” days and a peak of 494 on November 18, which was the joint second highest AQI ever recorded in the city.
Data also shows this is the first time the AQI has not dropped below 300 all November.
The lowest 4pm average AQI this month was 303 on November 27.
Last year, the average AQI was 373 and it was 321 in 2022. It was 328 in 2020, 312 in 2019, 335 in 2018, 361 in 2017, 374 in 2016 and 358 in 2015.
Delhi’s AQI has remained very poor since November 24, with the average AQI of 331 making Friday the sixth consecutive day.
CPCB classifies AQI between 0 and 50 as “good”, between 51 and 100 as “satisfactory”, between 101 and 200 as “moderate”, between 201 and 300 as “poor”, between 301 and 400 as “very poor”, and over 400 as “severe”.
Forecasts by the Centre’s Early Warning System for Delhi (EWS) also predict that “very poor” air will continue. “The air quality is likely to be in the ‘very poor’ category from November 30 till December 2,” said the forecast issued on Friday.
