Cold wave conditions abated on Thursday with the mercury rising by 3-4°C in most parts of Delhi even as the air quality deteriorated to the very poor category while isolated drizzle or very light rain was expected later in the day.
Safdarjung, the city’s representational weather station, recorded a minimum temperature of 5.6°C, a notch below normal but three notches higher than that of Wednesday’s 2.6°C. The rise in minimum temperatures was expected to continue over the next five days due to back-to-back western disturbances
Wednesday was the third successive cold wave day and the eighth this month. January has had the second-highest cold wave days in 31 years.
According to India Meteorological Department (IMD) data, Delhi recorded 12 such days in January 2008 and seven each in 1997, 1998, and 2021.
Five consecutive cold wave days were recorded between January 5 and January 9 this year, the highest in the last 31 years along with those in 2013. In 2008, the longest spell of consecutive such days was four.
The IMD declares a cold wave in the region when the minimum temperature is 4.5°C or more below the normal mark, or when it drops to 4°C or lower.
An IMD official said the first cold wave spell felt colder because of the northwesterly winds and fog, which rose to the upper level during the day and blocked sunlight. “This meant low daytime temperatures too. In this second spell, we have seen clear skies and the impact has been down to mainly strong cold northwesterly winds, which have been faster and stronger this time than in the last spell between January 5 and 9,” said the official.
The official said both the spells were after a snowfall in higher reaches and its subsequent impact was felt across the plains.
Two western disturbances were expected to bring rain to the city. “The first western disturbance will influence Delhi on January 19 [Thursday] and 20 [Friday], with chances of drizzle on Thursday night. The second will be more intense and will impact the western Himalayan region from the night of January 20 to January 26.”
The official said the plains of the northwest will be impacted from January 23 to 25 and light rain is expected on both days with wind speeds touching 30-40 km per hour on January 24.
There have been sunny days despite low minimum temperatures. A maximum temperature of 19.6°C was recorded on Wednesday. The mercury was expected to go up to 21°C on Thursday and Friday.
An Air Quality Index (AQI) of 322 (very poor) was recorded at 8am on Thursday compared to 306 at 4pm on Wednesday. It is likely to return to the poor category by Friday due to rain and an increase in wind speed.
An AQI between 0-50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, and over 400 severe.
