Heavy rain on Thursday night brought relief from the unusually sweaty conditions that prevailed for most of the day.

A Met official called them “pre-monsoon thundershowers”. More such spells are expected in the next few days, he said. Met officials said rain is not ruled out on Saturday when the city goes to the polls.

The Met office recorded around 65mm of rain in Alipore between 8.30pm on Thursday and 8.30am on Friday.

In Met parlance, 60mm or more in 24 hours translates to heavy rain.

The showers started after 10.30pm and picked up steam within a short span. The intensity of the showers went down in the early hours of the day. But the showers were persistent and continued well into Friday morning.

The rain cooled the city and for much of Friday, the weather was pleasant. The maximum temperature plunged to 27.5 degrees Celsius, eight notches below normal. The minimum was 23.7 degrees, four notches below normal.

On Thursday, it was around 34 degrees Celsius, a notch below normal. But the day felt extremely uncomfortable because of the high humidity level.

The maximum and minimum relative humidity were 87 per cent and 72 per cent.
As a result, people sweated profusely throughout the day.

“The rain was triggered by clouds that came from Jharkhand. As the clouds moved towards the coast, they caused rain in the districts as well,” said the official.

Monsoon update

The monsoon reached north Bengal on Friday, ahead of schedule, said a Met update.

“The southwest monsoon has advanced into the remaining parts of the northeast Bay of Bengal, some parts of the northwest Bay of Bengal, remaining parts of Tripura, Meghalaya and Assam and most parts of North Bengal and Sikkim.... It covered Darjeeling, Jalpaiguri, Kalimpong, Alipurduar and Coochbehar districts and some parts of North and South Dinajpur,” the Met bulletin said.

The usual date of the monsoon’s arrival in north Bengal is June 5.

Heavy rain is likely to continue in north Bengal till June 4, the Met bulletin said.

“The trough from northwest Uttar Pradesh to west Bangladesh across southeast Uttar Pradesh, south Bihar and Sub-Himalayan West Bengal and Sikkim at 0.9km above mean sea level persists.... strong moisture incursion over the region heavy to very heavy rainfall activity is very likely over some districts of north Bengal,” it said.

South Bengal is also expected to get rain, in the form of thunderstorms.

Met officials were still tight-lipped about the arrival of the monsoon in south Bengal, including Calcutta.

“It is unlikely till June 5. A low-pressure area is expected to take shape over the Bay of Bengal in the second week of June. The system is likely to affect the arrival of monsoon into south Bengal,” the Met official said.