Bengaluru is set for another spell of rain as a strengthening low-pressure system over the Bay of Bengal keeps weather conditions active across southern India. The India Meteorological Department (IMD) has forecast rain and thunderstorms over Karnataka through September 24, with heavy-rain warnings across all three Karnataka subdivisions.
Bengaluru rain forecast
Bengaluru recorded 9 cm of rainfall in the 24 hours ending Sunday morning, the highest reported total in South Interior Karnataka during that period. The IMD’s city forecast calls for cloudy conditions and rain or thundershowers on September 21, with thunderstorms and lightning. Rain or thundershowers accompanied by strong gusty winds are forecast for September 22.
The current city forecast indicates:
- September 21: Rain/thundershowers, with thunderstorms and lightning
- September 22: Rain/thundershowers with strong gusty winds
- September 23–24: Mainly cloudy conditions with light rain possible
- September 25–26: Light rain remains possible, but no specific warning is listed.
The IMD’s subdivision warning issued on September 20 lists heavy rain and thunderstorm/lightning warnings for South Interior Karnataka through September 24.
What is happening over the Bay of Bengal?
A low-pressure area formed over the north Andaman Sea and adjoining areas on September 19 and subsequently moved into the east-central Bay of Bengal.
The IMD expects the system to strengthen into a depression on September 21 and a deep depression on September 22 as it moves west-northwestwards. It is expected to approach the north Andhra Pradesh–south Odisha coast around September 23.
The system is therefore expected to have its strongest direct effects along the eastern coast, although its broader circulation is contributing to unsettled weather across parts of southern and central India.
Heavy rain across South India
Karnataka is not the only southern state experiencing active weather.
The IMD has forecast widespread rainfall over Coastal Karnataka, North Interior Karnataka and South Interior Karnataka, while Kerala, Tamil Nadu, Telangana, Andhra Pradesh and Rayalaseema are also expected to experience significant rain or thunderstorms.
Parts of Tamil Nadu, Rayalaseema and South Interior Karnataka could also experience gusty winds of 40–50 km/h, with higher gusts in some areas.
Andhra Pradesh and Odisha face the biggest impact
As the Bay system moves toward the coast, the heaviest rainfall is expected farther east.
The IMD has warned of heavy to very heavy rain over north Coastal Andhra Pradesh from September 22–24 and south Odisha from September 22–25. Isolated extremely heavy rainfall is possible over south Odisha and north Coastal Andhra Pradesh on September 23–24.
Telangana and Chhattisgarh are also expected to receive heavier rain as the system moves inland.
Why Bengaluru is seeing rain now
The current Bengaluru spell is part of a broader active-weather pattern rather than the city being directly in the path of the Bay of Bengal system.
Recent heavy showers have already produced waterlogging and traffic disruption in several parts of Bengaluru. The IMD’s continuing forecast indicates that unsettled conditions are likely to persist for several more days.
For commuters, the combination of heavy showers, thunderstorms and gusty winds means short periods of intense rain could cause localized flooding and slower traffic, particularly during peak hours.
Bottom line
Bengaluru can expect continued rain and thunderstorms this week, with the IMD maintaining heavy-rain warnings for Karnataka through September 24. Meanwhile, the strengthening Bay of Bengal system is expected to move toward the Andhra Pradesh–Odisha coast, where the most intense rainfall is forecast around September 23–24.
