Don't pull out your warm clothes yet because the weather is tipped to keep the city warm over the next few days.
The Celsius may have dipped below 18 degrees early on Friday but brace for a temperature rise and some dampness in the November air after a long run of cool mornings and clear skies that gave the north-westerly wind free rein.
"The coastal parts of Bengal, including many places in South 24-Parganas and East Midnapore, are likely to get rain in the next 48 hours. It is difficult to say at this moment whether Calcutta too will get rain. But we are not ruling it out," said Gokul Chandra Debnath, the director of the regional meteorological centre in Alipore.
Rainfall in Calcutta at this time of the year is unusual, though this November has already had 18.3mm so far. If the low-pressure system over the Bay moves closer to land over the next two days, night temperatures will rise throughout south Bengal.
"The skies have been clear on most days since Durga Puja, paving the way for the smooth flow of north-westerly winds from the colder parts of the country. That explains the nip in the air in Calcutta and the suburbs, but we might be seeing a change soon," said a weather scientist with the India Meteorological Department.
The moisture in the air and cloud cover that is likely to form over the city from Saturday afternoon could make the weather uncomfortable for Calcuttans, many of whom might have been hoping for an early winter this year.
"Currently, there is a lot of sunshine but we are not perspiring. With the added moisture in the air, it will become muggy," Debnath said.
The closer the low-pressure area moves to the land and the stronger it gets, more the chance of rain in Calcutta. The good news is that rain will help cool the city quickly and bring back the clear skies that characterise the season.
In five of the last 10 years, there has been no November rain in the city.