Tamil Nadu Rain Alert: Heavy Rain Forecast in 21 Districts, Chennai May See Thunderstorms

Tamil Nadu is likely to witness another spell of rain on Monday, September 21, with the Regional Meteorological Centre (RMC) forecasting heavy rainfall at isolated places across 21 districts. Chennai and its suburbs may also receive light to moderate rain accompanied by thunderstorms, particularly during the evening or night. The weather activity is linked to a low-pressure area over the Bay of Bengal, which is expected to intensify as it moves west-northwestward. The India Meteorological Department (IMD) has also flagged thunderstorms and lightning activity for Tamil Nadu and Puducherry.

21 Tamil Nadu Districts Under Heavy Rain Forecast

The districts likely to receive heavy rain are The Nilgiris, Coimbatore, Dharmapuri, Krishnagiri, Dindigul, Pudukkottai, Tiruvarur, Nagapattinam, Mayiladuthurai, Perambalur, Ariyalur, Kallakurichi, Villupuram, Tiruvannamalai, Sivaganga, Thanjavur, Madurai, Cuddalore, Tirupattur, Vellore and Tiruchirappalli. Chennai Weather Forecast & Update for Today, Monday, 21 September 2026: Expect Dense Drizzle and High Humidity, High of 33°C.

The forecast indicates that heavy rain could occur at isolated places, with thunderstorms, lightning and strong winds of around 40-50 kmph also possible in affected areas. Puducherry and Karaikal may experience similar conditions.

Chennai Weather Forecast

Chennai is not among the districts under the isolated heavy-rain forecast, but the city and surrounding areas may receive light to moderate showers with thunderstorms during the evening or night. The maximum temperature in Chennai is expected to remain around 35-36°C, while the minimum could be around 26-27°C.

Bay of Bengal System Behind Rainfall

The ongoing rainfall is associated with a low-pressure system over the North Andaman Sea and adjoining Bay of Bengal. The system is expected to move west-northwestward and strengthen further over the coming days. The weather system has already contributed to widespread rainfall across parts of Tamil Nadu. According to the latest RMC warning, Tamil Nadu and Puducherry face thunderstorm and lightning activity on September 21, while thunderstorm-related weather remains possible on September 22. IMD Issues Yellow Alert in Six Keralam Districts, Forecasts Isolated Heavy Rainfall.

Rainfall Likely to Ease From Tuesday

Rainfall activity is expected to gradually decrease across much of Tamil Nadu from Tuesday, although moderate rain may continue over the Western Ghats. Chennai and neighbouring districts including Tiruvallur, Kancheepuram and Chengalpattu could still receive isolated light to moderate showers later in the week. Residents in areas affected by thunderstorms and strong winds should follow the latest advisories issued by the meteorological authorities.

(The above story first appeared on LatestLY on Sep 21, 2026 10:40 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).