Delhi’s minimum temperature falls two notches, further drop in store

Delhi recorded a minimum temperature of 7.8 degrees Celsius on Sunday compared to 10.8°C on Saturday. The Palam observatory also recorded ‘cold day’ conditions, as maximum temperatures also dropped significantly below normal on Sunday.

The minimum temperature started dropping over many parts of northwest India including Delhi on Sunday, following a western disturbance that affected the western Himalayas on January 7 and 8.

Due to the prevalence of dry north or northwesterly winds over most parts of northwest India, the minimum temperature is likely to fall gradually by 3-4°C over the next three to four days, which may cause isolated cold wave conditions over Punjab, Haryana, Chandigarh, Delhi and north Rajasthan on January 12 and 13. (Representative Image) (HT_PRINT)

Delhi recorded a minimum temperature of 7.8 degrees Celsius on Sunday compared to 10.8°C on Saturday. The Palam observatory also recorded ‘cold day’ conditions, as maximum temperatures also dropped significantly below normal on Sunday. The station recorded a maximum temperature of 14.2°C, six below normal, while Safdarjung recorded 16.2°C, four below normal.

Due to the prevalence of dry north or northwesterly winds over most parts of northwest India, the minimum temperature is likely to fall gradually by 3-4°C over the next three to four days, which may cause isolated cold wave conditions over Punjab, Haryana, Chandigarh, Delhi and north Rajasthan on January 12 and 13.

Surface winds, between speeds of 15 and 25kmph are very likely over the plains of northwest India during next the three days, according to India Meteorological Department’s Sunday bulletin.

“Very cold northwesterly winds are blowing from snowclad Himalayas towards Delhi, so both maximum and minimum temperatures have fallen. Winds are blowing at 20 to 25 kmph, so the perception of cold is stronger. They are chilly winds. We are expecting cold day conditions over Delhi for the next few days,” said Kuldeep Srivastava, head, regional weather forecasting centre.

According to the IMD, a ‘cold day’ or ‘severe cold day’ is based on two parameters — a minimum temperature below 10°C and maximum temperature is 4.5 degree C or 6.4 degree C below normal respectively. A cold wave occurs in the plains when the minimum temperature is 10°C or below and/or is 4.5 notches lower than the season’s normal for two straight days.

A cold wave is also declared when the minimum temperature is less than 4°C in the plains. A cold day and cold wave together means the gap between day and night temperatures was lower than normal.

Air quality still poor

Despite very strong winds, Delhi recorded ‘poor’ air, with an AQI (air quality index) of 245 on Sunday. Strong winds and better ventilation conditions are likely to prevail between January 10 and 13. The air quality is likely to remain within the ‘poor’ and ‘moderate’ category on January 11 and 12, according to air quality early warning system for Delhi under the Union ministry of earth sciences.

“Delhi’s air quality improved to ‘poor’ category and is improving further. We are likely to see ‘moderate’ air quality for two to three days, due to strong winds,” said VK Soni, scientist at IMD’s air quality division.