By The Hindu Bureau

Copyright thehindu

Chennai woke up to another pleasant Saturday (September 20, 2025), thanks to the overnight showers that cooled the city.

Prevailing weather systems over the south Peninsular region triggered thunderstorm activity over parts of north Tamil Nadu. During the past 24 hours ending 8.30 a.m. on Saturday, the automatic rain gauges at Arakkonam in Ranipet district and Jaya Engineering College in Tiruvallur district received the maximum rainfall of 7 cm each. This was followed by Ambattur, Ayapakkam, and Korattur with 6 cm of rainfall each. Several other places in Tiruchi, Chennai, Tiruvallur, Cuddalore, Vellore, Nilgiris, Kancheepuram, Salem, Erode, and Pudukkottai districts also received light to moderate showers.

The widespread thunderstorm activity since Friday (September 19) night kept Saturday’s maximum temperature at 29 degree Celsius in Chennai at 11 a.m. The Regional Meteorological Centre has forecast that similar weather trend will continue over north Tamil Nadu, including Chennai, on Sunday (September 21).

Officials of the RMC noted that it was typical for places like Chennai to receive rainfall from convective activity in the evening or night hours during the Southwest monsoon.

In its Nowcast, the RMC predicted light to moderate rainfall likely over Chengalpattu district and light rainfall over Chennai, Villupuram, Tiruvallur, and Nilgiris until 1 p.m. on Saturday.

A low pressure area likely to develop over Northeast Bay of Bengal after September 25 would be one of the deciding factors on rainfall over Tamil Nadu.