Kolkata’s weather roller coaster isn’t done yet. The India Meteorological Department’s Regional Meteorological Centre (RMC) in Kolkata has extended its rain and thunderstorm warning for South Bengal through September 3, with gusty winds expected to touch 50 kmph in a few districts.
What’s Driving the Rain
The trigger is a well marked low pressure area that formed over the northwest Bay of Bengal and adjoining West Bengal-north Odisha coasts in the last week of August. By August 30, it was centred over the same stretch, with an associated cyclonic circulation extending nearly 7.6 km into the atmosphere, and IMD expected it to track west-northwest across north Odisha and Gangetic West Bengal. The monsoon trough itself currently runs from Amritsar through Muzaffarnagar, Gorakhpur, and Patna, before passing through Bankura and into the low pressure zone, then southeast into the Bay of Bengal.
Forecast for Kolkata and South Bengal
For September 1 and 2, IMD’s South Bengal forecast, which includes Kolkata, calls for light to moderate rain and thundershowers at most places, with heavy rain of 7 to 11 cm likely at isolated spots in Purulia, West Burdwan, and Birbhum. Thunderstorms with lightning and gusty winds of 30 to 40 kmph are forecast across all South Bengal districts, including Kolkata, Howrah, and both 24 Parganas.
The heaviest totals so far have landed outside the city: Bankura recorded 7 cm in the 24 hours to August 30, while Basirhat in North 24 Parganas logged 5 cm and Sagar Island in South 24 Parganas saw 3 cm. Kolkata itself has seen lighter spells, but the citywide thunderstorm and gusty wind warning still applies. This follows last week’s thunderstorm alert for the same region, part of what has been an unusually active stretch of the monsoon.
Looking further out, IMD expects light to moderate rain or thundershowers to continue at many places across South Bengal through September 6, so the wet spell isn’t wrapping up in the next day or two.
What Could Go Wrong
IMD’s bulletin flags a familiar set of risks for the city: temporary waterlogging in low lying areas and underpasses, lightning strikes in open spaces, and possible damage to weaker structures such as kutcha houses and unpaved roads. Kolkata’s usual trouble spots, including stretches along the E M Bypass service roads, Topsia, and parts of Behala, are the ones most likely to see standing water again if the predicted spells arrive on schedule, as covered in Kolkata Dekho’s monsoon commute survival guide.
IMD’s Advisory
The department’s standing advice applies through the alert period: take shelter during thunderstorms and lightning rather than waiting it out under a tree or near an electric pole, stay away from waterlogged areas and open water bodies, and expect traffic to be regulated on flood-prone stretches if rain intensifies. Fishermen have separately been advised not to venture into the Bay of Bengal off the West Bengal and Odisha coasts through the peak of the system.
Frequently Asked Questions
How long will Kolkata’s rain alert last?
IMD’s current bulletin covers South Bengal, including Kolkata, through September 3, with lighter rain and thundershower activity expected to continue at many places until around September 6.
Will Kolkata Metro and train services be affected?
IMD’s bulletin does not specifically flag metro or rail disruption, but past heavy spells have caused temporary waterlogging near low lying stations and underpasses, so delays are possible if rainfall intensifies.
Which areas of Kolkata are most at risk of waterlogging?
Chronic waterlogging pockets such as parts of the E M Bypass service roads, Topsia, and Behala tend to flood first when South Bengal gets heavy spells, based on the city’s recurring monsoon pattern.
The Bottom Line
This isn’t a one-day washout warning, it’s a multi-day pattern tied to a slow-moving low pressure system. Keep an umbrella handy through the week, avoid open fields and water bodies during thunderstorms, and budget extra travel time if you’re headed through Kolkata’s usual flood-prone stretches.
Source: India Meteorological Department, RMC Kolkata (Special Bulletin No. 3, August 30, 2026).
Editorial note: featured image still needed, suggested subject is a Kolkata monsoon skyline or waterlogged street photo. Please source a licensed stock or original photo before publishing.
