Another wet spell is coming, the Met office has said.

“A cyclonic circulation lies over Gangetic West Bengal and neighbourhood at 3.1km above mean sea level. Under favourable synoptic conditions and strong moisture incursion from Bay of Bengal, thunderstorms... activities are very likely to occur over the districts of West Bengal,” said a Met bulletin on Sunday.

Some parts on the northern fringes of Calcutta received isolated spells of drizzle on Saturday and Sunday. Uniform and widespread rain is expected in the city and elsewhere in the state on Monday.

“Thunderstorms with lightning and gusty winds are likely across south Bengal on Monday. The intensity could be more in Birbhum, Murshidabad, Nadia, North and South 24-Parganas and East Burdwan districts,” said a Met official.

In north Bengal, the system is expected to trigger rain across the districts. Jalpaiguri, Cooch Behar and Alipurduar are likely to get heavy rain on Monday.

Calcutta and the most of south Bengal have already suffered multiple heat assaults this season.

One of the longest spells of scorching conditions was broken by a wet spell that began on May 6. But the past few days have been very hot and humid.

On Sunday, the sky shifted between being sunny and cloudy. The clouds prevented the day temperature from shooting up. The Met office recorded a maximum of 36.6 degrees in Alipore. But the high humidity levels aggravated the discomfort index. For the better part of the day, the humidity was above 60 per cent.

The Met bulletin said thunderstorms are likely in south Bengal on Tuesday and Wednesday as well. “But on Monday, they are expected to be uniform and widespread,” said an official.