The Northeast monsoon has shifted into a vigorous phase, bringing intense spells of rain overnight across Tamil Nadu, particularly the north coastal districts.

The spell of wet weather is expected to continue till October 26, 2026 with a low pressure area forming over southwest Bay of Bengal off Tamil Nadu during early hours of Wednesday (October 21). A trough runs from the centre of this low pressure area over Bay of Bengal and adjoining Tamil Nadu coast to north coastal Andhra Pradesh. The system is being monitored for further strengthening.

Rainfall in Chennai

Multiple weather systems over the Bay of Bengal are expected to sustain intense rainfall across the State this week. Several areas in and around Chennai received heavy overnight downpour, with MGR Nagar in Chennai topping the charts with 15 cm in the 24- hour period ending 8.30 a.m. on Wednesday.

Torrential downpour had pounded several areas in Chennai and fringes – Vadapalani (14 cm), Saidapet, Meenambakkam, Alandur, Kancheepuram (13 cm each); DGP office, Madipakkam, Valasaravakkam, Maduravoyal (12 cm each); Nungambakkam, Nerkundram, Adyar (11 cm each); Korattur (10 cm) and Ambattur, Saligramam, Puzhal, R.A. Puram, Ayapakkam, YMCA Nandanam, Parrys , Anna University, Manali, Anna Nagar West and Pozhichalur, (9 cm each).

Widespread showers across districts

Many other districts, including Kanniyakumari, Kancheepuram, Tiruppur, Ramanathapuram, Tenkasi and Virudhunagar too received moderate to heavy spells of rain.

Rain-bearing clouds continued to sweep across various parts of Tamil Nadu, sustaining the wet spell on Wednesday.

Another low pressure area: RMC

In its latest update, the Regional Meteorological Centre (RMC) in Chennai has noted that low pressure area over Southwest Arabian sea is likely to move towards the Somalia coast and may not have significant impact over Tamil Nadu region. The weather agency has also forecast another low pressure area brewing over Southeast and adjoining east central Bay of Bengal around October 23.

The RMC is monitoring the system for its strength and movement for any potential rainfall impact over Tamil Nadu. The system is currently represented by an upper air cyclonic circulation over Gulf of Thailand and adjoining Myanmar region, far away from Tamil Nadu.

As the monsoon remains active and weather systems line up over the seas, the southern and delta districts of Tamil Nadu are likely to receive more intense spells as Wednesday (October 21) progresses.

South coastal districts including Thoothukudi, Tirunelveli and Kanniyakumari are in the path of very heavy rainfall till Thursday (October 22) morning. Various south, delta and interior districts, including Karur, Dindigul, Pudukottai and Thanjavur also have prospects of heavy rainfall.

After a spell of soaring temperatures this June, Chennai and its fringes will experience cool weather on Saturday (June 20, 2026), with strong northeasterly winds bringing in moisture.

The mercury level in the city was around 32 degree Celsius at 10 a.m. on Saturday, much lower than its average temperature of 37 degree Celsius recorded in June. However, humidity level was high at 75%.

This was much lower than the day temperature of 37.9 degree Celsius recorded in Chennai on Friday (June 19). Palayamkottai had registered a hottest temperature of 39 degree Celsius in the State on Friday.

The Regional Meteorological Centre (RMC) has said that a broad cloud band located about 80-100 km east-northeast of Chennai over the Bay of Bengal is likely to increase cloud cover across the city and suburbs. Humidity level would also see a spike.

Chennai may be spared soaring temperatures as daytime temperatures would remain one to three degree Celsius below normal due to reduced sunshine. Stronger sea breeze would help sustain moist onshore winds.

Possibility of thundershowers

Though widespread heavy rainfall may not be possible, north coastal areas, including Chennai, will experience light to moderate thundershowers in isolated areas. The city may enjoy a cloudier, slightly cooler but more humid weather on Saturday. However, the RMC has noted no major rainfall event is expected in Chennai for the day.

During the past 24 hours ending 8.30 a.m. on Saturday, Aavoor in Thiruvarur district received heavy rainfall of 14 cm, which was the highest rainfall recorded in the State. Various other weather stations in delta and interior districts too received moderate to heavy rainfall.

In its Nowcast valid till 1 p.m. on June 20, the RMC has predicted light to moderate rainfall with thunderstorms and lightning in districts, including Chennai, Kancheepuram, Vellore, Ranipet, Tiruvallur, Pudukottai, Erode, and Villupuram. Rainfall may affect traffic in some areas and also cause waterlogging, the RMC has said.