The deficit is likely to persist with subdued rains predicted for September. (Representational)
Delhi recorded just 41.6 mm of rainfall in August, the lowest in at least 14 years, due to the absence of any major weather system in northwest India.
Weather experts attribute the lack of rainfall this month to the development of three low-pressure areas over the northwest Bay of Bengal which pulled the monsoon trough over central India and did not let it move to the north for a long period.
According to IMD data, the Safdarjung Observatory recorded a paltry 41.6 mm of rainfall against a normal of 247 mm in August, the wettest month of the year.
Data available on the India Meteorological Department website show the capital recorded 214.5 mm of rainfall in August last year, 237 mm in 2020, and 119.6 mm in 2019.
Forecasters said a good spell of rain is unlikely in Delhi over the next five to six days though cloudy weather will prevail.
"Three low-pressure areas (LPAs) developed over the northwest Bay of Bengal in August which travelled across Odisha, Chhattisgarh, Madhya Pradesh, Rajasthan, and south Pakistan, giving good rains there," Mahesh Palawat, vice president (climate change and meteorology), Skymet Weather.
"The LPAs kept the monsoon trough south of its normal position for a long time. Delhi and other parts of northwest India received rain only when the trough passed over the region while moving to the foothills of the Himalayas," he said.
Usually, the trough is seen running through Sri Ganganagar, Delhi, Allahabad, Jharsuguda, Kolkata, and the North Bay of Bengal.
Normally, two to three LPAs develop in the Bay of Bengal in August, of which one or two move towards the northwest, increasing rainfall in the Indo-Gangetic plains, Mr Palawat said.
The weather bureau had predicted normal to above normal rainfall in August over northwest India.
Overall, the Safdarjung Observatory has logged 352.4 mm of rainfall against a normal of 516.9 mm since June 1 when the monsoon season usually starts clocking a deficit of 31 per cent.
The deficit is likely to persist with subdued rains predicted for September.
A bountiful monsoon had yielded 1,169.4 mm of rainfall last year, the third highest since 1901.
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