Monsoon rains arrive in Delhi, Mumbai same day

The monsoon arrived in Delhi and Mumbai, the India Meteorological Department (IMD) declared on Sunday, making it the first time since 1961 when the annual rains arrived on the two megapolises — 1,500km apart — at the same time.

The normal date of monsoon onset for Mumbai is June 11 and for Delhi June 27, but this year, the rainclouds followed an unusual path to cover the country with a lag over several western states.

“The last time the monsoon covered both Delhi and Mumbai at the same time was June 21, 1961. That year, the monsoon covered the remaining parts of the country on the same day,” said an IMD official on Sunday, asking not to be named. Till this weekend, the rains had mostly covered the southern peninsula and parts of east and northeast India.

Safdarjung, which represents Delhi’s weather, recorded 48.3mm of rainfall in a 24-hour period till 8.30am on Sunday — most of it being recorded in the early hours. Another 2.4mm of rainfall was added between 8.30am and 5.30pm, IMD data showed.

These overcast conditions meant Delhi’s maximum stayed below 30 degrees Celsius through the day and was recorded at 29.0 degrees Celsius at Safdarjung — eight degrees below normal and the lowest for June in at least 12 years, IMD data showed. The last time Delhi had a lower maximum in June was June 9, 2010, when it was 26.9 degrees Celsius.

The IMD has a yellow alert in place for Monday and Tuesday, forecasting light to moderate showers across the city. A green alert is in place from Wednesday onwards, with light rain expected from Wednesday until Saturday, making it a wet end to the month, officials said.

“The Southwest monsoon has further advanced into remaining parts of Central Arabian Sea, some parts of north Arabian Sea, remaining parts of Maharashtra including Mumbai, Madhya Pradesh and Uttar Pradesh, Delhi, some parts of Gujarat, Rajasthan and Haryana, remaining parts of Uttarakhand and most parts of Himachal Pradesh and some more parts of Jammu, Kashmir and Ladakh on June 25,” said IMD in its monsoon bulletin on Sunday, stating conditions were favourable for the monsoon to advance into some more parts of Gujarat, Rajasthan, Haryana, Punjab and the remaining parts of Jammu and Kashmir in the next 48 hours.

Among other stations, Lodhi road received 59.6mm of rainfall in a 24-hour period till 8.30am, Ayanagar 54mm, Ridge 27.4mm, Palam 29.6mm, Jafarpur 60mm and Mungeshpur 48mm. Between 8.30am and 5.30pm, the highest rainfall of 25mm was recorded at Mungeshpur, followed by 19.5mm at Jafarpur.

The IMD classifies it as very light rainfall when it is between trace and 2.4mm in a 24-hour period. It is light rainfall when it is between 2.5mm and 15.5mm; as moderate between 15.6mm and 64.4mm and heavy rainfall when over 64.4mm is recorded in a single day.

Last year, the onset was declared over Delhi on June 30, making it three days late. In 2021, the monsoon reached Delhi 16 days late, on July 13 — its most delayed onset since 2002.

This is the earliest arrival of the southwest monsoon in Delhi since 2020 and 2015, when it arrived on the same date — June 25. The last time it arrived sooner than this was in 2013, when it reached Delhi on June 16.

Till 5.30pm on Sunday, Delhi recorded 73.8mm of rainfall so far this month. The long-period-average (LPA) for Delhi for June is 74.1mm, which is likely to be breached on Monday, with more rain forecast.

The rain also meant Delhi’s minimum was recorded at 23.1 degrees Celsius — five degrees below normal. It was 30.4 degrees a day earlier. Delhi’s maximum on Saturday was 37.4 degrees. Forecasts show Delhi’s maximum is likely to hover around 30 degrees Celsius on Monday, with the minimum hovering around 23 degrees Celsius.

In terms of air quality, Delhi’s air returned to the satisfactory category following moderate showers across the city on Sunday. Delhi’s 24-hour average air quality index (AQI) stood at 71 (satisfactory) as per Central Pollution Control Board’s national bulletin at 4pm on Sunday. It was 169 (moderate) a day earlier at the same time. The AQI is forecast to remain in the satisfactory category on Monday too.