Heavy rain alert for south Bengal Tuesday–Friday as Bay depression deepens
Synopsis
A deepening Bay of Bengal depression is set to drench south Bengal from Tuesday to Friday, with Yellow rain alerts covering up to seven districts by week's end and gusts of 40–50 kmph forecast for coastal areas. Fishermen have been banned from the sea across three state coastlines, and Kolkata — already running below normal temperatures — is in for a wet stretch.
Key Takeaways
The IMD has forecast heavy rain in south Bengal from Tuesday, 22 September to Friday, 25 September 2026 .
A depression from the north Andaman Sea is expected to deepen into a deep depression over the east-central Bay of Bengal by Monday.
Yellow alerts are in place across up to seven districts by Friday, including North and South 24 Parganas , East Midnapore , Birbhum , Murshidabad , Nadia , and East Burdwan .
Coastal gusts of 40–50 kmph are expected in South 24 Parganas and East Midnapore from Wednesday.
Fishermen are banned from the central and north Bay of Bengal Monday through Friday, and from waters off West Bengal , Odisha , and Bangladesh coasts from Wednesday to Friday.
Kolkata recorded a maximum of 29.02°C on Sunday — 3.06°C below normal — with relative humidity between 79% and 98% .
The India Meteorological Department (IMD) on Monday, 21 September 2026, forecast heavy rainfall across large parts of south Bengal from Tuesday to Friday, triggered by a low-pressure system that formed in the Bay of Bengal and is expected to intensify into a deep depression. The warning covers multiple districts and includes a Yellow alert in several coastal and inland areas through the week.
How the System Developed
According to the IMD, a cyclone strengthened in the north Andaman Sea before turning into a clear depression on Sunday. The system is tracking west and northwest and is likely to deepen into a deep depression over the east-central Bay of Bengal by Monday. Such Bay of Bengal depressions in late September are a well-established seasonal pattern, often bringing sustained multi-day rainfall to coastal and sub-coastal Bengal.
District-Wise Alert Breakdown
Scattered rain and thundershowers are expected in south Bengal on Tuesday, intensifying through the week. Key alerts include:
Tuesday: A Yellow alert for heavy rain in East Midnapore, parts of North 24 Parganas, and South 24 Parganas; gusty winds of 30–40 kmph across all districts.
Wednesday: Yellow alert extended to South 24 Parganas, East Midnapore, West Midnapore, and Jhargram; coastal districts of South 24 Parganas and East Midnapore may see gusts of 40–50 kmph.
Thursday: Alert covers South 24 Parganas, East Midnapore, West Midnapore, Birbhum, and Murshidabad; rain is forecast to increase slightly.
Friday: The widest alert of the week — seven districts under Yellow alert: North 24 Parganas, South 24 Parganas, East Midnapore, Birbhum, Murshidabad, Nadia, and East Burdwan; gusts of 40–50 kmph expected in coastal parts.
North Bengal Outlook
North Bengal faces a quieter start to the week, with little chance of heavy rain until Wednesday. However, the forecast turns wetter by Thursday, with a Yellow alert issued for Darjeeling and Jalpaiguri. By Friday, the alert expands to Darjeeling, Kalimpong, Alipurduar, Cooch Behar, Jalpaiguri, and North Dinajpur.
Fishing Ban and Kolkata Conditions
Fishermen have been prohibited from venturing into the central and north Bay of Bengal from Monday, with the ban extended through Friday. A separate ban covers waters off the coasts of Bangladesh, Odisha, and West Bengal from Wednesday to Friday. In Kolkata, rain chances remain low on Monday but are expected to climb from Tuesday, with the highest probability from Wednesday to Friday. On Sunday, the city recorded a maximum temperature of 29.02°C — 3.06°C below normal — and a minimum of 24.06°C, which is 1.07°C below normal; relative humidity ranged between 79% and 98%. With the depression likely to consolidate further, conditions in coastal and south Bengal could deteriorate quickly over the next 48 hours.
Point of View
But the scale of this alert — seven districts on Yellow by Friday and a fishing ban stretching across three state coastlines — signals a system with meaningful intensity. What gets less attention in routine weather coverage is the compounding risk: waterlogged paddy fields ahead of the kharif harvest, and the coastal fishing communities that absorb the most economic damage from multi-day sea bans. The IMD's district-level granularity has improved markedly in recent years, yet the gap between a Yellow alert and actionable evacuation or livelihood support for fishermen remains a policy blind spot that state agencies routinely fail to close in time.
NationPress
21 Sept 2026
Frequently Asked Questions
Why is heavy rain forecast in West Bengal this week?
Heavy rain is forecast in West Bengal from Tuesday to Friday due to a low-pressure system that formed in the north Andaman Sea, strengthened into a depression, and is expected to deepen into a deep depression over the east-central Bay of Bengal by Monday, 21 September 2026. The system is tracking west and northwest, directing moisture toward coastal and south Bengal.
Which districts in south Bengal are under a Yellow rain alert?
By Friday, seven districts are under a Yellow alert: North 24 Parganas, South 24 Parganas, East Midnapore, Birbhum, Murshidabad, Nadia, and East Burdwan. Alerts begin as early as Tuesday in East Midnapore and parts of North and South 24 Parganas, expanding progressively through the week.
Is north Bengal also affected by the rain forecast?
North Bengal faces a quieter start, with low rain probability until Wednesday. However, a Yellow alert is issued for Darjeeling and Jalpaiguri on Thursday, expanding to Darjeeling, Kalimpong, Alipurduar, Cooch Behar, Jalpaiguri, and North Dinajpur on Friday.
What restrictions are in place for fishermen?
Fishermen have been banned from the central and north Bay of Bengal from Monday, with the ban continuing through Friday. An additional ban covers waters off the coasts of West Bengal, Odisha, and Bangladesh from Wednesday to Friday. The IMD advises all fishing boats to return to shore before conditions worsen.
What is the current weather situation in Kolkata?
Kolkata recorded a maximum temperature of 29.02°C on Sunday — 3.06°C below normal — and a minimum of 24.06°C, which is 1.07°C below normal, with relative humidity ranging from 79% to 98%. Rain chances in the city are low on Monday but are expected to rise from Tuesday, with the highest probability from Wednesday to Friday.
