Heavy rain alert for 11 Tamil Nadu districts today; temperatures to rise
Synopsis
Tamil Nadu faces a split weather signal on 30 September: the IMD has flagged heavy rain and 40–50 km/h gusts for 11 districts and Karaikal, yet daytime temperatures could still climb up to four degrees above normal — a combination that points to high humidity stress even in districts receiving no rain. The Nilgiris and Coimbatore stay on watch through Thursday as well.
Key Takeaways
The IMD has issued a heavy rain alert for 11 Tamil Nadu districts and Karaikal on 30 September 2026 .
Affected districts include Nilgiris , Erode , Salem , Dharmapuri , Krishnagiri , Mayiladuthurai , Nagapattinam , Tiruvarur , Thanjavur , Pudukkottai , and Tiruchirappalli .
Wind gusts during thunderstorms could reach 40–50 km/h across rain-affected zones.
Maximum temperatures may rise up to 4°C above normal in Tamil Nadu despite the rain outlook.
Moderate rain is also expected in Puducherry and several northern, central and southern Tamil Nadu districts.
A heavy rain watch for Nilgiris and Coimbatore extends into Thursday, 1 October .
The India Meteorological Department (IMD) has forecast heavy rain accompanied by thunderstorms and gusty winds at isolated places across 11 Tamil Nadu districts and Karaikal on Wednesday, 30 September 2026, even as maximum temperatures in the state are expected to rise above normal by up to four degrees Celsius. The dual weather signal — intense localised rain alongside hotter-than-usual daytime conditions — reflects the complex atmospheric pattern currently gripping the region.
Districts Under Heavy Rain Alert
The IMD has identified the following districts as likely to receive heavy rainfall: Nilgiris, Erode, Salem, Dharmapuri, Krishnagiri, Mayiladuthurai, Nagapattinam, Tiruvarur, Thanjavur, Pudukkottai, and Tiruchirappalli. Wind speeds during thunderstorms could reach 40 to 50 kilometres per hour, the department noted.
Despite the rainfall warning, temperatures across Tamil Nadu are projected to exceed seasonal norms on Wednesday, with departures of up to four degrees Celsius above the average maximum — a pattern that can intensify heat stress even during rainy spells.
Moderate Rain Likely in Several Other Districts
Beyond the heavy-rain zones, moderate showers accompanied by thunder, lightning and gusty winds are expected in several other parts of the state. Districts in this category include Tirupattur, Vellore, Ranipet, Ariyalur, Perambalur, Karur, Villupuram, Cuddalore, Madurai, Sivaganga, Ramanathapuram, and Thoothukudi. The union territory of Puducherry is also likely to receive moderate showers with thunderstorm activity, with wind gusts in the same 40–50 km/h range.
Light rain with thunder and lightning remains possible at a few scattered locations elsewhere across Tamil Nadu.
What Is Driving the Weather
The IMD attributed the conditions to an atmospheric circulation over northern Tamil Nadu and adjoining southern coastal Andhra Pradesh, extending to approximately 1.5 kilometres above sea level. A trough running from southern Telangana to the Gulf of Mannar — passing through Rayalaseema, northern Tamil Nadu and adjoining southern coastal Andhra Pradesh — at an altitude of roughly 0.9 kilometres is reinforcing the system.
Separately, a deep depression that was located over the northern Andaman Sea and the adjoining Myanmar coast on 28 September moved north-northwestward and crossed the Myanmar coast east of Kyaikto between 7.30 pm and 9.30 pm. While that system has moved away from Indian shores, its earlier track contributed to the current moisture-laden conditions over the Bay of Bengal and the eastern coast.
Thursday Outlook: Nilgiris and Coimbatore on Watch
For Thursday, 1 October, the IMD has forecast heavy rain at isolated locations in the Nilgiris and Coimbatore districts, with thunderstorms and gusts of 40 to 50 km/h likely. The rest of Tamil Nadu, along with Puducherry and Karaikal, may receive light to moderate rain with accompanying thunder, lightning and strong winds through Thursday.
Residents in the identified districts — particularly in low-lying coastal and ghat areas — are advised to stay alert to local civic advisories as the two-day weather window unfolds.
Point of View
When moist Bay of Bengal air generates intense but patchy convective storms without cooling the overall surface much. What deserves attention here is the trough stretching from southern Telangana to the Gulf of Mannar: that alignment historically concentrates rainfall over the delta districts of Nagapattinam, Tiruvarur and Thanjavur, areas already prone to flooding. Civic preparedness in those districts — drainage clearance, NDRF positioning — matters more than the rainfall headline itself.
NationPress
30 Sept 2026
Frequently Asked Questions
Which Tamil Nadu districts are under a heavy rain alert on 30 September 2026?
The IMD has forecast heavy rain for 11 districts: Nilgiris, Erode, Salem, Dharmapuri, Krishnagiri, Mayiladuthurai, Nagapattinam, Tiruvarur, Thanjavur, Pudukkottai, and Tiruchirappalli, along with Karaikal. Thunderstorms and wind gusts of 40–50 km/h are also expected in these areas.
Why are temperatures rising even though it is raining in Tamil Nadu?
The IMD has forecast maximum temperatures up to four degrees Celsius above normal across Tamil Nadu on 30 September, even as heavy rain is expected in parts of the state. This is a feature of pre-northeast-monsoon convective weather, where intense but localised storms can coexist with higher daytime heat in non-rain areas.
What is causing the heavy rain in Tamil Nadu right now?
The IMD attributes the conditions to an atmospheric circulation over northern Tamil Nadu and adjoining southern coastal Andhra Pradesh, extending to about 1.5 km above sea level. A trough from southern Telangana to the Gulf of Mannar is reinforcing the system, and residual moisture from a deep depression that crossed the Myanmar coast on 28 September is also a contributing factor.
Will the rain continue into Thursday, 1 October?
Yes. The IMD has forecast heavy rain at isolated locations in the Nilgiris and Coimbatore districts on Thursday, 1 October. Light to moderate rain with thunder and gusty winds is also expected across the rest of Tamil Nadu, Puducherry, and Karaikal through Thursday.
Is Puducherry also affected by the rain forecast?
Puducherry is expected to receive moderate showers accompanied by thunderstorms and wind gusts of 40–50 km/h on Wednesday, according to the IMD forecast. Light to moderate rain is also likely in Puducherry on Thursday.
