Surplus annual rainfall in Delhi; temp drops sharply

The Capital on Saturday woke up to overcast skies, which persisted throughout the day, with sudden bursts of downpours taking the total rainfall past its annual long-period average amid a sharp dip in mercury levels

The Capital on Saturday woke up to overcast skies, which persisted throughout the day, with sudden bursts of downpours taking the total rainfall past its annual long-period average amid a sharp dip in mercury levels.

Delhi received 29.8mm of rainfall on Saturday , taking its total annual rainfall to 814.5mm, against its annual long-period average (LPA) of 774.4mm, according to IMD. (RAJ K RAJ /HT PHOTO)

Delhi received 29.8mm of rainfall on Saturday, taking its total annual rainfall to 814.5mm, against its annual long-period average (LPA) of 774.4mm, according to the India Meteorological Department (IMD). To be sure, Delhi crossed the annual LPA rainfall on Friday evening, when it received 32.6mm in the spell ending 5.30pm.

The IMD has stated that light to moderate rain is likely on Sunday, with multiple spells of rain expected during the day. However, the IMD has not forecast any rain from Monday to Friday. “After Sunday, rains will subside, as westerly winds start flowing through the city,” said Dahiya.

According to IMD, while Delhi has recorded surplus rainfall this year—with around four months still left in the year—its neighbouring states are staring at deficits. Haryana is facing a deficit of 21%, Rajasthan 26%, and Punjab 37%, while Delhi has seen an excess of 10% rainfall during the same period.

Experts stated that the region to the west of Delhi, as a whole, has seen a deficit due to a lack of weather activity over the region. “There are three factors which determine rain in north India: the movement of the monsoon axis, low pressure areas from the Bay of Bengal, and western disturbances. Delhi has received rain mostly through the axis this time. Only three low pressure areas came this year, and did not travel as far as they usually do, into south Rajasthan and Gujarat,” amateur meteorologist Navdeep Dahiya said.

“Additionally, sometimes, they interact with an approaching western disturbance and cause heavy rain over the region, but that also did not happen often this year, aside from the current spell of rain over Delhi,” he added.

The continuous rainfall has also led to a sharp drop in the temperatures, with the city recording a maximum temperature of 27.6 degrees Celsius (°C), which was 6.5°C below normal and 7.5°C lower than the maximum of 35.1°C recorded a day earlier.

The minimum temperature was only 2.8°C lower than the maximum, clocking at 24.8°C, which fell by 3.4°C from a day earlier and was around 1°C lower than the normal.

Between 8.30am and 5.30pm on Saturday, Chattarpur recorded the highest rainfall in the city, at 39.5mm, followed by 35.6mm rainfall at Palam, 30.8mm of rainfall at Lodhi Road, and 29.8mm of rainfall at Safdarjung, where Delhi’s base station is located.

The city’s air quality has also been steadily improving since September 1, due to a mix of rain and wind speed. According to Central Pollution Control Board data, the city recorded an average AQI of 113 on September 1, in the “moderate” category, followed by readings of 85, 74 and 71 on September 2, 3, and 4, respectively, all of which were in the “satisfactory category”. On Saturday as well, the city recorded a “satisfactory” AQI of 59.

The 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”.