July ended with 70 per cent surplus rainfall but August so far has recorded a 25 per cent deficit in the city.
Between August 1 and 16, the city received 151.6mm of rain, according to the Met office. The usual volume is 202.3mm, said a Met official.
Successive weather systems and the position of the monsoon trough had delivered surplus rainfall to Calcutta and the rest of south Bengal in June and July.
In August, however, the absence of such systems has contributed to the deficit so far.
The previous low-pressure area over the Bay of Bengal had taken shape near the Odisha-Andhra coastline on August 13. The system moved northwest and, on Saturday, it was over south Chhattisgarh and its neighbourhood.
A fresh low-pressure area is likely to form over the northwest and adjoining west-central Bay of Bengal on Monday, said a Met report.
“The system is expected to take shape in the same area as the previous one, closer to the Andhra-Odisha coastline, and follow the same path. It will not have much impact on south Bengal. Southern Odisha and northern Andhra Pradesh will be more affected,” the Met office said.
In Calcutta, hot and humid days are in store, with sporadic showers. The discom-
fort index will continue to be on the higher side, the Met said. Time spent outdoors will be taxing, especially during the day.
Around 1pm on Saturday, the temperature was around 32 degrees Celsius. But the high humidity of over 60 per cent made it feel like 40 degrees.
Independence Day was also hot and humid. More than 35 children, taking part in the celebrations on Red Road, reported sick at the end of the show and had to be taken to SSKM Hospital.
Chief minister Mamata Banerjee visited the students at the hospital with Kolkata Police commissioner Manoj Verma and other senior officers. She said the weather left some of the children dehydrated.
The students were later discharged from the hospital.
“The discomfort index is likely to remain on the higher side. There is some moisture near the surface. With sufficient heating, some rain is always likely. But consistent and widespread rainfall is unlikely until a system takes shape on or near the north Bay,” said a Met official.
On Saturday morning, the monsoon trough was passing through Rajasthan, Madhya Pradesh, Chhattisgarh and Andhra Pradesh before moving into east-central Bay of Bengal.
For most of July, the trough was passing through south Bengal. It moved up at the start of this month, triggering heavy rain in north Bengal.
Now that the trough has descended, the rains have subsided in north Bengal as well.