South Bengal red alert: Heavy rain forecast till Tuesday, Kolkata waterlogged
Synopsis
A deepening low pressure system over the northwest Bay of Bengal has pushed the Met office to issue a red alert for three south Bengal districts, with Kolkata already waterlogged and fishermen warned off the coast. The system is expected to intensify into a depression by Monday evening before rainfall eases from Tuesday evening — a narrow but disruptive window.
Key Takeaways
The RMC Kolkata issued a red alert for Bankura , West Midnapore , and Jhargram for heavy to very heavy rain on Tuesday, 18 August .
A low pressure area over the northwest Bay of Bengal is expected to deepen into a depression by late Monday .
Gale winds of 40–50 km/h prompt a ban on fishermen venturing into the north Bay of Bengal till Tuesday.
Kolkata recorded a minimum temperature of 25°C on Monday — 1.5 degrees below normal — as heavy rain caused widespread waterlogging and traffic disruption.
Rain is forecast to ease across south Bengal from Tuesday evening ; no further weather warning has been issued beyond that.
Heavy rain also expected in north Bengal districts including Jalpaiguri , Kalimpong , Alipurduar , and Darjeeling through Tuesday.
The Regional Meteorological Centre (RMC) in Kolkata on Monday, 17 August issued a forecast of heavy to very heavy rain across south Bengal districts, including Kolkata, through Tuesday, driven by an active low pressure area over the northwest Bay of Bengal and intensifying monsoon winds. A red alert has been issued for Bankura, West Midnapore, and Jhargram districts for Tuesday.
Low Pressure Deepening into Depression
According to the RMC, the low pressure area that formed over the northwest Bay of Bengal became more pronounced through Monday and is expected to strengthen into a depression by late Monday evening. The monsoon axis currently extends from the low pressure zone through Punjab, Haryana, Uttar Pradesh, and Jharkhand before reaching the Bay, funnelling sustained rainfall into the region.
Isolated heavy rainfall is also expected on Tuesday across West Midnapore, Jhargram, Purulia, Bankura, West Burdwan, and Birbhum districts. The remaining south Bengal districts will see rain with thundershowers. The weather office indicated that rainfall will begin to ease across south Bengal from Tuesday evening onwards, with no further weather warning issued beyond that period.
Fishermen Advisory and Sea Conditions
Gale-force winds of 40 to 50 kilometres per hour are currently blowing over the sea due to the low pressure system. The weather department has advised fishermen not to venture into the north Bay of Bengal off the coasts of West Bengal and Odisha until Tuesday. The advisory covers both the open sea and near-shore zones along the two state coastlines.
North Bengal Also Under Watch
Heavy rain is forecast to continue in north Bengal through Tuesday as well. On Monday, heavy rainfall is likely in Jalpaiguri and Kalimpong districts, while Alipurduar and Darjeeling are expected to receive heavy rain on Tuesday. Scattered rain with thundershowers will persist across North Dinajpur, South Dinajpur, Malda, and Cooch Behar through the same period.
Kolkata Waterlogged, Traffic Disrupted
Heavy rain that began in Kolkata from Monday morning left several areas waterlogged, causing significant traffic slowdowns in and around the city. The minimum temperature recorded in Kolkata on Monday morning stood at 25 degrees Celsius, which is 1.5 degrees below normal. The maximum temperature on Sunday was 30 degrees Celsius, 1.9 degrees below normal, reflecting the sustained cloud cover and precipitation suppressing daytime heat.
With the system expected to intensify before weakening, residents across south Bengal have been urged to remain cautious through Tuesday before conditions improve.
Point of View
Which means the Tuesday evening easing forecast carries real uncertainty. Kolkata's chronic drainage deficit means even a few hours of intense rain translates into hours of waterlogging, and the city's traffic grid has no meaningful buffer. The fishermen's advisory, covering both West Bengal and Odisha coasts, signals that the system's wind field is already wide — worth watching if it organises further overnight.
NationPress
17 Aug 2026
Frequently Asked Questions
Which districts are under red alert for rain in West Bengal?
The Regional Meteorological Centre has issued a red alert for Bankura, West Midnapore, and Jhargram districts for heavy to very heavy rainfall on Tuesday, 18 August. These three districts face the highest rainfall risk as the low pressure system intensifies.
Why is there heavy rain in south Bengal right now?
An active low pressure area over the northwest Bay of Bengal, combined with a monsoon axis stretching through Punjab, Haryana, Uttar Pradesh, and Jharkhand, is channelling sustained heavy rainfall into south Bengal. The system is expected to deepen into a depression by late Monday, further intensifying the rain.
When will the rain stop in Kolkata and south Bengal?
According to the RMC, rainfall is expected to ease across south Bengal from Tuesday evening onwards. No further weather warning has been issued beyond that period, suggesting a return to more normal conditions by Wednesday.
Are fishermen allowed to go to sea near West Bengal and Odisha?
No. Fishermen have been advised not to venture into the north Bay of Bengal off the West Bengal and Odisha coasts until Tuesday, due to gale-force winds blowing at 40 to 50 kilometres per hour over the sea.
Is north Bengal also affected by the current weather system?
Yes. Heavy rain is forecast to continue in north Bengal through Tuesday. Jalpaiguri and Kalimpong are expected to receive heavy rain on Monday, while Alipurduar and Darjeeling face heavy rain on Tuesday. Scattered rain with thundershowers will continue in North Dinajpur, South Dinajpur, Malda, and Cooch Behar.
