At 12.3°C, Delhi finally feels the winter chill

New Delhi
The minimum temperature dipped markedly on Tuesday, aided by persistent cold northwesterly winds in the region, to record a season-low of 12.3 degrees Celsius (°C). This also snapped a streak of higher-than-average minimum temperatures that the Capital has been recording since October 17.
According to data available from the India Meteorological Department (IMD), this is the most-delayed dip of minimum temperature to below the 15°C mark since 2011. It has also been a fairly warm start to November, picking up from one of the warmest Octobers the Capital has ever recorded.
Until November 18, Delhi’s average minimum temperature was 17.07°C, almost three degrees above the expected (average) long-period minimum temperature of 14.2°C for the November 1-18 period.
Forecasts show Delhi’s minimum temperature is likely to hover around 12°C till Thursday, before marginally rising by 1-2°C as the wind direction begins to fluctuate. Before Tuesday, the lowest minimum temperature recorded this winter was 15.3°C, on November 16.
“We have been recording cold northwesterly winds since November 12 and that has led to a gradual drop in the minimum temperature. In the early hours of Tuesday, we saw dense fog cover begin to lift and clear from Delhi, leading to improved visibility and this led to radiation cooling, which occurs when skies are relatively clear and the heat trapped by the surface is able to escape into the atmosphere,” IMD scientist RK Jenamani said.
He said that before this, a thick layer of fog was preventing the minimum temperature from dropping sharply. On Tuesday, Safdarjung recorded a minimum visibility of 600 metres, a great improvement from a visibility of 100 metres recorded a day before.
The weather recorded at the Safdarjung observatory is considered representative of Delhi’s overall weather, but other weather stations recorded much cooler temperatures. Among the lowest were the Ridge station in north Delhi, which clocked a low of 8.8°C, and the Lodhi Road station, which clocked a low of 11°C.
The day’s maximum temperature, meanwhile, was 25.4°C, which was two degrees below the normal. It was 23.5°C a day earlier, a season-low. Across Delhi, the lowest maximum on Tuesday was 23.2°C, recorded at the Palam observatory.
Warm start to winter
The onset of winter has been slow this year, with higher-than-average day and night temperatures recorded all through October, making it the warmest October since 1951, according to IMD data. The average monthly maximum and minimum temperature this October were 35.1°C and 21.2°C, respectively—they were 36.2°C and 22.3°C, respectively, in 1951.
The same trend carried into November, until Tuesday, due to a lack of western disturbances. “Until western disturbances bring sufficient snowfall to the mountains and rainfall to the plains, mercury does not drop substantially. Although we have seen spells of snow in November, a dense layer of fog from November 13 has meant night-time temperature is unable to dip quickly. The fog creates a lid, trapping some heat,” said Mahesh Palawat, vice president at Skymet meteorology.
This was the first instance of the minimum temperature dipping below 15°C this year, already 22 days later than last year. In 2023, the temperature fell to 14.3°C on October 28. This happened much earlier in 2022, when the minimum temperature fell to 14.5°C on October 23. In 2021, the minimum temperature breached the 15°C mark on October 27, clocking 14.6°C and in 2020, a minimum temperature of 13.7°C was recorded on October 20.
The last time there was as much delay in the drop was in 2015, when the minimum temperature fell below the 15°C mark, to 11°C, on November 18.
According to long-period data, the minimum temperature in Delhi can dip below 10°C towards the end of the month, with the lowest minimum temperature last November being 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).
Forecasts for Wednesday said the maximum temperature will likely hover around 25°C, and the minimum will remain around 12°C.