Delhi has witnessed the wettest monsoon in the last 46 years. In 1975 monsoon rain over Delhi was 1150 mm, followed by 2003 when it was 1050 mm. In 2010 it was 1035.5mm. Until September 11 this year, Delhi has received 1110.5 mm rain.
Moreover, in the last 24 hours, heavy showers have lashed the national capital resulting in three digit rains to the tune of 103 mm over Palam. In fact, the Indira Gandhi International Airport has been waterlogged with water along with streets of Delhi seeing waterlogging in many areas.
Onset of monsoon was delayed over Delhi by 16 days. Normal date of monsoon arrival in Delhi is June 27, but first monsoon rain occurred over National capital on July 13. Despite late arrival, few heavy rain spells helped Delhi to surpass monthly average of July. And July ended with surplus of 141 % with total rainfall of 507.1 mm.
Talking about the month of September, In September 2010, Delhi witnessed 332 mm rain. Until now, which is just 11 days, 343 mm rain has been recorded over Delhi.
We expect moderate showers with few heavy rains to continue for another 24 to 36 hours over Delhi NCR. Chances are high for monsoon 2021 to become the wettest monsoon ever for Delhi NCR.
The heavy rain in the month of September can be attributed to the number of low-pressure areas as a developing power bi of Bengal and travelling in West North West direction. These weather systems are enhancing the flow of humid winds from Bay of Bengal and moisture feed is available up to mid tropospheric levels.