New Delhi: As the much-anticipated winter chill continues to evade Delhi-NCR, the region is experiencing a troubling rise in air pollution despite recent slight temperature drops. India recorded its warmest October since 1901, with the mean temperature exceeding normal levels by 1.23 degrees Celsius. According to the India Meteorological Department (IMD), November is also expected to remain warm, offering no signs of approaching winter.
October’s mean temperature was reported at 26.92 degrees Celsius, the highest since 1901, compared to the usual 25.69 degrees Celsius. Additionally, the average minimum temperature was 21.85 degrees Celsius, against the normal 20.01 degrees Celsius.
Typically, winter in Delhi begins in late November or early December and extends until the first week of March. IMD Director General Mrityunjay Mohapatra explained that the warmer conditions have been caused by the absence of western disturbances and the presence of easterly winds, driven by active low-pressure systems in the Bay of Bengal. He noted that north-westerly winds are necessary for temperatures to decrease, and monsoonal wind patterns have also contributed to the delayed cooling.
Forecasts suggest that temperatures in the north-western plains will continue to be 2-5 degrees above normal for at least the next two weeks before gradually declining. The IMD clarified that November is not considered a winter month, with true winter conditions typically becoming evident in December. The delayed onset of winter is also attributed to persistent neutral El Niño conditions in the equatorial Pacific Ocean.
Looking forward, there is a higher likelihood of La Niña conditions developing gradually during November and December. As per reports, Mohapatra pointed out that ENSO (El Niño–Southern Oscillation) patterns are shifting towards negative values, hinting at the potential arrival of La Niña by December. He acknowledged that global weather agencies had mispredicted El Niño behaviour this year.
La Niña, associated with cooler ocean surface temperatures in the central and eastern equatorial Pacific, often results in good monsoon rainfall across the Indian subcontinent. During winter, La Niña typically causes a cold jet stream that flows through Afghanistan, Iran, and the Hindu Kush mountains, bringing colder conditions to India. While global models had not observed La Niña during the southwest monsoon, the IMD had earlier indicated the possibility of a severe winter in northern India, particularly in the northwest and central regions, due to the potential emergence of La Niña.
In years influenced by La Niña, northern India, especially the northwest and adjacent central regions, often experiences colder-than-average temperatures, leading to the risk of cold waves. Meanwhile, the IMD forecasts that the northeast monsoon will bring above-normal rainfall to the southern peninsula in November, affecting areas like Tamil Nadu, Puducherry, Karaikal, Coastal Andhra Pradesh, Rayalaseema, Kerala, Mahe, and southern interior Karnataka. Most parts of the country are expected to receive normal to above-normal rainfall, except for northwest and some central regions.