Bengaluru over the last few days may have been witnessing heavy rainfall, but the southwest monsoon rainfall pattern between June 1 and September 30 reveals a different story. According to the India Meteorological Department (IMD) data, during this period the Bengaluru city station recorded 313 mm rainfall with a departure of -236 mm.
While the Bengaluru station recorded a deficit of -236 mm rainfall between June 1 and September 30, the HAL station received 434 mm rainfall with a deficit of -29 mm. The Kempegowda International Airport received 391 mm rainfall, while the deficit for the station is not available.
A post by an X handle said that the city witnessed the driest southwest monsoon in the last 20 years. “The IMD observatory at Bengaluru sees the driest southwest monsoon in 20 years by recording just 313.3 mm of rainfall against an average of 597.7 mm for the period between Jun 1st to 30th Sept. Previously the observatory had recorded 298.3 mm in the SWM season of 2006,” @BngWeather posted on X.
Overall, as per IMD seasonal cumulative rainfall data, Karnataka received 564.6 mm rainfall against the normal 831.8 mm with a departure of -32%.
Among the districts Bengaluru South (earlier Ramanagara) has received the highest deficit with -87%, followed by Kalaburagi and Hassan with -55% and -53%, respectively. Bengaluru Urban district received 258.7 mm rainfall against the normal 452.4mm with a deficit of -43 %.
IMD Officials have attributed the rainfall deficit to strong El Nino, which delayed the onset of the southwest monsoon in Karnataka.
Karnataka has three meteorological subdivisions — Coastal Karnataka, North Interior Karnataka and South Interior Karnataka.
Coastal Karnataka received 2,228.3 mm rainfall against the normal 3,093.9 mm rainfall with a departure of -28 %. North Interior Karnataka received 329.8 mm against the normal 480.8 mm with a departure of -31%. South Interior Karnataka received 433.7 mm against the 678.4 mm with a departure of -36 %.
“As forecast, we are witnessing strong El Nino conditions which has severely impacted the southwest monsoon in the State,” IMD Scientist C.S Patil said.
Published – September 30, 2026 11:14 pm IST


