The Regional Meteorological Centre (RMC) has forecast that Northeast monsoon rainfall may commence over the southern peninsula from Thursday (October 15, 2026).

This comes as welcome news to large parts of Tamil Nadu that have sweltered through a prolonged spell of warm weather. Dark clouds had already begun gathering over coastal parts of the State like Chennai, signalling a shift in weather conditions.

Chennai experienced intermittent showers and a cloudy sky on Wednesday (October 14, 2026). Moderate rainfall is expected to continue on Thursday (October 15, 2026), with the temperature likely to remain close to the normal range of 33-34°C

Nagapattinam and Karaikal received rainfall of 9 cm and 8 cm each till 6 p.m., while various other places such as Dharmapuri, Virudhunagar, and Ramanathapuram received light to moderate rainfall.

The Northeast monsoon is likely to bring fairly widespread rainfall over the State till October 20, 2026, putting an end to the extended spell of soaring temperatures in interior districts. On Wednesday (October 14, 2026), Erode recorded the highest maximum temperature of 37.8°C in the State.

Monsoon indicator

RMC officials said the reversal of the wind pattern to Easterlies had begun, indicating the arrival of monsoon. Fairly widespread rain has already begun in south coastal Tamil Nadu and is expected to spread to the north coastal region and other areas as well.

Southwest monsoon is expected to retreat entirely from the country on Thursday (October 15, 2026). The prevailing weather systems, including those over the Comorin area, would influence rainfall over the State.

The RMC has forecast heavy to very heavy rainfall over isolated places in various coastal and Western Ghats districts on Thursday (October 15, 2026). Similar rainfall trends are likely in several interior districts till October 20, 2026. The wet spell would bring temperatures closer to normal from Friday (October 16, 2026), said officials.