Chennai, Dec 31 (PTI) Tamil Nadu concluded the 2025 northeast monsoon season with a slight rainfall deficit of about 3 per cent, but Tirunelveli district recorded a remarkable 95 per cent increase in rainfall this
year, B Amudha, Director of the Regional Meteorological Centre, said here on Wednesday.
"As a whole, Tamil Nadu received 42.72 cm of rainfall against the normal 44.12 cm. However, this falls under the ‘normal’ category, which is classified as having a range of +19 to -19 per cent," the director told PTI.
According to India Meteorological Department (IMD) data, Tirunelveli received 100.5 cm of rainfall between January 1 and December 31, compared with its usual 51.4 cm.
Other districts, including Virudhunagar, Tiruvarur, Ranipet, Ramanathapuram, and Tenkasi, recorded excess rainfall ranging from 15 per cent to 39 per cent.
Conversely, a few pockets experienced significant deficits, with Chengalpet at the top at 35 per cent below normal, followed by Perambalur at 30 per cent.
Other districts in the deficit category include Krishnagiri, Salem, Dharmapuri, Tiruppur, Karur, Tiruchirapalli, Dindigul, and Kancheepuram.
Chennai recorded a 10 per cent rainfall deficit, receiving 72.5 cm against the normal 80.7 cm. While north and central districts received early monsoon rains, southern districts benefitted from late showers, ensuring a relatively balanced distribution, Amudha said.
IMD data also showed that October was the best-performing month, with about 23 cm of rainfall—36 per cent above the climatological normal—supported by an active early monsoon phase and earlier synoptic systems.
Rainfall weakened sharply thereafter, with November receiving around 15 cm against the usual 17 cm, and December recording only 4.5 cm compared with the normal 9 cm, pulling down the seasonal average, Amudha said.
"During December, we did not get the expected normal rainfall. December ended with a 49 per cent deficit," she added.
Weather experts and officials attributed the shortfall to the absence or weakening of favourable Bay of Bengal systems in November-December, despite a strong start in October.
"There were no major synoptic systems like troughs of low pressure, easterly waves, or upper-air cyclonic circulations, which usually generate rainfall activity," the director noted. PTI JR SSK
