IMD heavy rain alert: Coimbatore, Nilgiris, Kanyakumari on watch as Bay of Bengal low-pressure forms
Synopsis
A low-pressure system over the northwestern Bay of Bengal is set to intensify within 48 hours, triggering heavy rain warnings for Coimbatore, the Nilgiris, and Kanyakumari. While direct landfall is not expected, the system's moisture is enough to disrupt life across Tamil Nadu — and local administrations are already on alert.
Key Takeaways
The IMD has issued a heavy rainfall warning for Coimbatore , the Nilgiris , and Kanyakumari on 4 July .
A low-pressure area has formed over the northwestern Bay of Bengal and is expected to intensify over the next 48 hours .
The system is not forecast to make direct landfall in Tamil Nadu but will significantly enhance rainfall across the state.
Moderate rainfall is predicted over north Tamil Nadu , Puducherry , and Karaikal ; light to moderate showers expected elsewhere.
Maximum temperatures in Tamil Nadu , Puducherry , and Karaikal are likely to stay below normal on Saturday and Sunday .
Residents in low-lying and hilly areas have been advised to remain alert; local administrations are on standby.
The India Meteorological Department (IMD) has issued a heavy rainfall warning for Coimbatore, the Nilgiris, and Kanyakumari districts on Saturday, 4 July, after a low-pressure area formed over the northwestern Bay of Bengal and adjoining regions. The weather system is expected to intensify over the next 48 hours, raising the likelihood of widespread rainfall across large parts of Tamil Nadu.
What the IMD Alert Says
In its weather bulletin issued on Saturday, the IMD warned that the western and southern districts — particularly Coimbatore, the Nilgiris, and Kanyakumari — face a heightened risk of waterlogging, localised flooding, and disruptions in vulnerable areas. Residents in low-lying and hilly regions have been specifically advised to stay updated on weather advisories and exercise caution during periods of intense rainfall.
Beyond these three districts, the IMD has predicted moderate rainfall over north Tamil Nadu and the Union Territories of Puducherry and Karaikal. The remaining parts of the state are expected to receive light to moderate showers.
The Low-Pressure System Explained
The rainfall activity is being driven by the evolving low-pressure system over the Bay of Bengal, which meteorologists expect to become more organised over the next two days. Notably, the system is not forecast to make direct landfall in Tamil Nadu at this stage; however, its associated moisture and circulation are sufficient to significantly enhance rainfall across the state.
This comes amid the active southwest monsoon season, when Bay of Bengal systems routinely amplify rainfall over peninsular India. The IMD has said it will continue to closely monitor the system's progress and issue updated forecasts as conditions evolve.
Impact on Temperatures
Maximum temperatures across Tamil Nadu, Puducherry, and Karaikal are likely to remain slightly below normal on both Saturday and Sunday, owing to increased cloud cover and widespread rainfall. The cooler daytime conditions are expected to offer temporary relief from the recent warm spell experienced across several parts of the state.
Precautionary Measures
Local administrations across the affected districts have been urged to monitor the situation closely and implement precautionary measures wherever necessary. Authorities have been put on alert for possible waterlogging and localised flooding, particularly in low-lying coastal and hilly zones. The IMD's advisory underscores the importance of preparedness as the system gains strength over the coming days.
Point of View
But this one warrants attention because the Nilgiris and Kanyakumari — both hilly, landslide-prone districts — are in the direct impact zone. The IMD's framing of a 48-hour intensification window means the risk window is narrow but consequential. What the bulletin does not yet clarify is whether the system could organise further into a depression, which would materially change the rainfall distribution. Local administrations would do well to pre-position disaster response assets now rather than wait for an upgraded alert.
NationPress
4 Jul 2026
Frequently Asked Questions
Which districts are under heavy rain alert in Tamil Nadu on 4 July?
The IMD has placed Coimbatore, the Nilgiris, and Kanyakumari under a heavy rainfall warning on 4 July. These western and southern districts face the highest risk of waterlogging and localised flooding.
What is causing the heavy rainfall forecast in Tamil Nadu?
A low-pressure area has formed over the northwestern Bay of Bengal and adjoining regions. The system is expected to intensify over the next 48 hours, enhancing moisture and rainfall activity across Tamil Nadu.
Will the low-pressure system make landfall in Tamil Nadu?
According to the IMD, the system is not expected to directly make landfall in Tamil Nadu at this stage. However, its associated moisture and circulation are sufficient to significantly increase rainfall across the state.
What precautions has the IMD advised for residents?
The IMD has advised residents — especially those in low-lying and hilly areas — to stay updated on weather advisories and exercise caution during intense rainfall. Local administrations have also been urged to take precautionary measures and monitor the situation closely.
How will temperatures be affected in Tamil Nadu this weekend?
Maximum temperatures across Tamil Nadu, Puducherry, and Karaikal are likely to remain slightly below normal on Saturday and Sunday due to increased cloud cover and widespread rainfall, offering temporary relief from the recent warm spell.
