How Bengaluru almost broke the driest-ever August record

This August could well have been the driest on record for Bengaluru if not for one spell of intense rains in the final hours of the 31st.

From August 1 to 31 (until 8.30 pm), the IMD's Bengaluru city observatory received only 12.6 mm of rainfall and the HAL airport 14.4 mm. The numbers for the previous driest-ever August were 20.6 mm (1885) and 22 mm (1999), respectively. The mean monthly total rainfall for Bengaluru city is 162.7 mm and HAL airport 133.6 mm.

But as torrential rains pounded the city from 9 pm onwards, records changed dramatically. Bengaluru city recorded 64.8 mm of rain in the last three hours to 11.30 pm. The HAL airport received 52 mm in the last three hours to 11.30 pm.

The last-minute changes notwithstanding, this August did break several weather records. The month was the warmest-ever for Bengaluru with 20 days of above-normal temperatures. It also recorded the highest-ever minimum temperature (22.9°C) and the second-highest maximum temperature (32.6°C), according to the IMD.

Heavy rain lashes in the city on Thursday Night, in Bengaluru. 

IMD officials attributed August's "crazy" extreme weather to El Niño, which refers to the warming of the Pacific Ocean surface. El Niño disrupted the formation of weather systems, including low-pressure areas, depression and upper air circulation.

In Bengaluru, the situation was worsened by rising greenhouse gas emissions and increased surface ozone content, A Prasad, the head of the IMD's meteorological centre in Bengaluru, told DH.

Before Thursday, the city had just one rainy day in the entire month. The IMD defines a rainy day when precipitation is 2.5 mm or more.

Another IMD official, CS Patil, said the weather was "too sultry".

"I haven't seen such weather in August in the last 20 years, at least," he said.

In September, the city's wettest, IMD has forecast slightly below normal rainfall and above normal rainfall between 8 and 14, Prasad said.