Tamil Nadu rain: Why is the southern state receiving heavy showers in January? Check IMD forecast, reason and more

Tamil Nadu, Puducherry and Karaikal are likely to receive heavy rainfall from January 8 as a deep depression in the Bay of Bengal is likely to bring heavy showers to the south. A system over the Bay of Bengal has moved northwestwards with a speed of 10kmph, the IMD said in its weather bulletin, triggering significant rainfall across coastal and interior regions. The system over the Bay of Bengal is likely to consolidate into a deep depression and bring heavy rain to Tamil Nadu in a rare January weather event. This weather system is likely to bring scattered rainfall, particularly over the coastal parts of Tamil Nadu, for three days from Friday (January 9, 2026). Since 1981, the Bay of Bengal has witnessed only 20 intense weather systems in January, reports The Hindu.

"The deep depression over southwest Bay of Bengal moved nearly northwestwards with a speed of 10 kmph during past 6 hours, and lay centred at 2330 hours IST of yesterday, the 8th January, 2026 over the same region, near latitude 6.7°N and longitude 83.6°E, about 200 km east-southeast of Pottuvil (Sri Lanka), 240 km east-southeast of Batticaloa (Sri Lanka), 280 km east-northeast of Hambantota (Sri Lanka), 330 km southeast of Trincomalee (Sri Lanka), 630 km southeast of Karaikal (Puducherry) and 800 km south-southeast of Chennai (Tamil Nadu). It is very likely to continue to move northwestwards and cross Sri Lanka coast between Pottuvil and Trincomalee around evening/night of 9th January 2026," the IMD said in its latest weather bulletin.

"Heavy to very rainfall accompanied with thunderstorm, lightning very likely at isolated places over Tamil Nadu on 9th & 10th and heavy rainfall at isolated places likely over Kerala on 10th January, 2026," the IMD said in its weather bulletin. Meanwhile, north India is reeling under dense fog conditions with dense to very dense fog likely across Punjab, Haryana, Chandigarh, and Delhi. Similar hazardous conditions are expected in Uttar Pradesh and Rajasthan, with visibility likely dropping to zero in several pockets.


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Why is Tamil Nadu receiving rainfall?

In an unusual January weather development, a system over the Bay of Bengal is expected to intensify into a deep depression by Thursday (January 8, 2026), bringing the likelihood of heavy rainfall to parts of Tamil Nadu. Historically, the Bay of Bengal has recorded only 20 intense weather systems during January since 1891, underscoring the rarity of the event.

B. Amudha, Head, (Additional in-charge), RMC, told The Hindu it is unusual for such intense weather systems to form over the Bay of Bengal in January. Climate change may also be influencing recent changes in weather trends. But reasons behind such increase in intense weather systems need further study,Y.E.A. Raj, former deputy director general of meteorology, Chennai told the outlet.

Tamil Nadu, Kerala to receive heavy rainfall

The IMD has predicted heavy to very rainfall accompanied with thunderstorm, lightning in Tamil Nadu for Friday and Saturday. Rainfall intensity will peak on January 10, with a gradual reduction expected January 11-12, though isolated heavy rain may still occur in the north coastal and adjoining interior districts. Kerala is likely to receive rainfall at isolated places on January 10.

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In Chennai, the sky condition is likely to be generally cloudy and light rain is likely, the Regional Meteorological Department said. Mist or haze during morning hours in some areas, it added. Light to moderate rain is likely in Mayiladuthurai, Chennai, Chengalpattu, Cuddalore, Villupuram, Nagapattinam,Thanjavur, Thiruvarur, Ramanathapuram, Pudukottai districts of Tamil Nadu and Karaikal, Puducherry areas.

Sea condition is very likely to be rough to very rough along & off Tamil Nadu-Puducherry coasts during January 8 to 10 and improve gradually thereafter, the IMD said. Sea condition is very likely to be very rough to rough over southeast Bay of Bengal on 8th January, it said. Fishermen are advised not to venture into the southwest Bay of Bengal and the adjoining East Equatorial Indian Ocean from January 8 to 10; the adjoining areas of the southeast Bay of Bengal on January 8 and 9; along and off the Sri Lanka coast, the Gulf of Mannar, and the adjoining Comorin and South Tamil Nadu coast from January 8 to 10; and along and off the North Tamil Nadu–Puducherry coast on January 9 and 10.

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Which Tamil Nadu districts will receive rainfall

The RMC has issued orange and yellow weather alerts, indicating the possibility of intense downpour up to 20 cm in some districts. On Friday, the downpour would be restricted to delta districts and south-coastal Tamil Nadu. While Tiruvarur and Navaratnam may receive heavy to very heavy rainfall, Ramanathapuram, Pudukottai, Mayiladuthurai, and Thanjavur are likely to receive heavy rainfall.

On Saturday (January 10), many coastal districts and some interior places may get rainfall, and it may be intense over the stretch between Chengalpattu and Ramanathapuram. While four districts, including Cuddalore and Tiruvarur, may receive heavy to very heavy rainfall, heavy rainfall may occur in isolated places in seven districts, including Pudukottai, Chengalpattu, and Ariyalur.