This October has been the warmest in at least 13 years, in terms of both minimum and maximum temperatures, according to India Meteorological Department (IMD) data. The average maximum temperature this month, till the 30th, was 35 degrees Celsius (°C), which was two degrees higher than the long-period average (LPA), and the minimum was 21.4°C, which was 1.9°C higher than the LPA.
Delhi has failed to record any rain this month, with the dry and dusty weather also making it the most polluted October in four years, according to Central Pollution Control Board (CPCB) data.
The temperatures were the highest since 2011, the oldest data available on IMD’s website. IMD did not share monthly data before that.
Experts said that a lack of western disturbances in the northern plains meant no snowfall was recorded in the higher reaches, with rain missing since the withdrawal of the monsoon across the plains. “It has been a dry October. We have seen warmer easterly to southeasterly winds dominate the month. Briefly, we had cold northwesterly winds and there was a dip in temperature, but even then, with no snowfall occurring in the mountains, a further dip in terms of night-time temperature did not happen,” said Mahesh Palawat, vice president at Skymet meteorology.
Delhi’s minimum temperature on Wednesday was 21°C, which was five degreesabove the normal, up from 20.3°C recorded a day earlier. The minimum temperature in Delhi can dip down to around 14°C by the end of October. In 2020, it fell as low as 12.5°C.
Days have been equally warm. The maximum was 36.1°C on Wednesday. It was 35.8°C a day earlier, which was five notches above the normal.
An IMD official said western disturbances not only bring snowfall and rainfall to the higher reaches at this time of the year, but even cloudiness in the plains can regulate temperature. “We have seen mostly clear skies. This can lead to low night-time temperature, but winds have also not remained northwesterly for too long,” the official said.
According to IMD data, Delhi receives 15.5mm of monthly rainfall in October, based on its LPA. However, this year, Delhi has recorded zero rainfall in October.
Palawat said that the lack of rainfall is also bound to impact Delhi’s air quality, with dust and particulate matter (PM) being prominent pollutants.
According to CPCB data, Delhi’s average air quality index (AQI) of 231 this October is its highest since 2020, when it was 265 (“poor”). The average AQI was 219 (“poor”) last October; 210 (“poor”) in 2022 and 173 (“moderate”) in 2021. In 2019, it was 234 (“poor”); 269 (“poor”) in 2018; 285 (“poor”) in 2017; 271 (“poor”) in 2016 and 264 (“poor”) in 2015.
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”.
“Lack of rainfall means pollutants cannot settle down and often, hover over the city. Then, one requires strong winds for dispersion and even that has been missing,” Palawat added.
IMD has forecast cool northwesterly winds to return from Wednesday, which is likely to lead to a dip in both maximum and minimum temperatures, by around 1-2°C, over the weekend. However, officials said a significant dip is unlikely.
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