IMD forecasts heavy rain in Tamil Nadu for 3 days, thunderstorms likely
Synopsis
The IMD has flagged a three-day heavy rain window for Tamil Nadu, with the zone of impact expanding from northern interior districts on Thursday to a wider southern arc — including Madurai and Virudhunagar — by 2 May. A low-altitude atmospheric trough stretching from Karnataka to the Gulf of Mannar is driving the activity, even as coastal areas brace for heat-humidity discomfort.
Key Takeaways
The IMD issued a heavy rainfall advisory for Tamil Nadu on 29 April 2025 , valid for the next three days.
A lower-atmospheric trough at 0.9 km altitude, running from north interior Karnataka to the Gulf of Mannar , is driving the weather system.
Heavy rain forecast for Nilgiris, Coimbatore, Erode, Salem, Dharmapuri, Krishnagiri on Thursday; coverage expands to Madurai, Sivaganga, Virudhunagar by 2 May .
Chennai to see partly cloudy skies with maximum temperatures of 38–39°C and a minimum of 28°C .
High humidity and heat may cause discomfort in coastal areas including Puducherry and Karaikal .
Residents in rain-prone districts advised to stay alert for thunderstorms and localised heavy showers.
The India Meteorological Department (IMD) on Wednesday, 29 April 2025, forecast heavy rainfall across parts of Tamil Nadu over the next three days, with several districts expected to experience thunderstorms and moderate to intense showers. The advisory was issued by the Regional Meteorological Centre Chennai, citing an active lower-atmospheric weather system over the region.
Weather System Behind the Forecast
According to the Regional Meteorological Centre Chennai, a trough in the lower atmosphere persists at an altitude of around 0.9 km, extending from north interior Karnataka to the Gulf of Mannar and passing through south interior Karnataka and Tamil Nadu. This weather system is expected to trigger widespread rainfall activity across the state over the coming days.
Coastal districts along the Western Ghats, as well as parts of southern Tamil Nadu, the delta regions, and Karaikal, are likely to receive light to moderate rain accompanied by thunderstorms at isolated places on Wednesday.
District-wise Forecast: Thursday to May 2
For Thursday, 1 May 2025, the IMD has forecast heavy rainfall at isolated locations in the districts of Nilgiris, Coimbatore, Erode, Salem, Dharmapuri, and Krishnagiri. The intensity is expected to persist on 1 May, with heavy rain likely in Nilgiris, Coimbatore, Erode, Tiruppur, Dindigul, and Theni districts.
On 2 May, heavy rainfall may occur at isolated places in Nilgiris, Coimbatore, Tiruppur, Dindigul, Theni, Madurai, Sivaganga, and Virudhunagar districts, indicating a continuation of active weather conditions across interior Tamil Nadu. Notably, the geographic spread of the forecast widens progressively over the three-day window, suggesting the weather system may be intensifying or shifting southward.
Temperature and Humidity Outlook
Maximum temperatures across Tamil Nadu, Puducherry, and Karaikal are expected to remain largely unchanged until 3 May, although a slight increase cannot be ruled out. The IMD has cautioned that high temperatures combined with elevated humidity levels could lead to significant discomfort in coastal areas, including Puducherry and Karaikal.
In Chennai, the sky is expected to remain partly cloudy on Wednesday, with the city likely to record a maximum temperature of around 38–39 degrees Celsius and a minimum of about 28 degrees Celsius, with warm and humid conditions prevailing through the day.
Advisory for Residents
Authorities have advised residents, particularly those in rain-prone districts, to remain alert for sudden weather changes including thunderstorms and localised heavy showers over the coming days. This comes amid the broader pre-monsoon season, when the Western Ghats districts of Tamil Nadu are historically susceptible to sharp, localised downpours that can cause flash flooding and disruption to road connectivity. The IMD is expected to issue updated bulletins as the weather system evolves.
Point of View
Drawing in more populous districts like Madurai and Virudhunagar by 2 May. What the bulletin does not address is preparedness — Tamil Nadu's drainage infrastructure in delta and interior districts has historically struggled with sudden pre-monsoon bursts. With temperatures simultaneously staying elevated and humidity rising, the compounded heat-rain stress on coastal communities is a public health dimension that official advisories tend to understate.
NationPress
1 May 2026
Frequently Asked Questions
Which Tamil Nadu districts are under heavy rain warning from the IMD?
The IMD has forecast heavy rain at isolated locations across Nilgiris, Coimbatore, Erode, Salem, Dharmapuri, and Krishnagiri on Thursday, expanding to Tiruppur, Dindigul, Theni, Madurai, Sivaganga, and Virudhunagar by 2 May 2025.
What is causing the heavy rainfall in Tamil Nadu?
A trough in the lower atmosphere at around 0.9 km altitude, extending from north interior Karnataka to the Gulf of Mannar through Tamil Nadu, is the primary driver of the widespread rainfall activity, according to the Regional Meteorological Centre Chennai.
What is the weather forecast for Chennai on 29 April 2025?
Chennai is expected to have partly cloudy skies on Wednesday with a maximum temperature of 38–39 degrees Celsius and a minimum of around 28 degrees Celsius. Warm and humid conditions are likely to prevail through the day.
Will temperatures rise in Tamil Nadu during the rain period?
Maximum temperatures across Tamil Nadu, Puducherry, and Karaikal are expected to remain largely unchanged until 3 May, though the IMD noted a slight increase cannot be ruled out. High humidity combined with heat may cause discomfort, especially in coastal areas.
What precautions has the IMD advised for Tamil Nadu residents?
Authorities have advised residents — particularly in rain-prone districts — to remain alert for sudden weather changes including thunderstorms and localised heavy showers over the coming days. Updated bulletins from the IMD are expected as the weather system develops.
