Bengaluru Weather: Rainy Weekend As Thunderstorms May Return To The City From May 15

After a week of dry and warm weather, Bengaluru may finally see a fresh spell of pre-monsoon showers later this week. While a few parts of the city witnessed light rain over the previous weekend, the showers were too scattered to provide lasting relief from the rising daytime temperatures and humidity levels.

The dry conditions come just days after Bengaluru recorded one of its heaviest rain spells of the season. On April 30, the city received nearly 111 mm rainfall within 24 hours, triggering waterlogging and traffic disruptions across several areas. However, rainfall activity weakened significantly afterward.

According to available weather observations, Bengaluru city observatory recorded only 31 mm rainfall during the first 13 days of May, while the HAL observatory registered just 8.2 mm against the monthly average of 110.4 mm. The sharp rainfall deficit has once again pushed temperatures upward across the city and surrounding regions.

Weather models now indicate that moderate to heavy showers are likely to return between May 15 and May 17. A few isolated areas may also witness light evening showers as early as tomorrow, especially during late afternoon and nighttime hours.

The latest weather developments are linked to a low-pressure area over the Bay of Bengal, which is gradually becoming more marked while moving away from the Indian coastline. As the system shifts farther into the sea, its peripheral winds are influencing weather patterns across southern India.

Currently, northeasterly winds are moving along the South Andhra Pradesh coast, while northerly winds are sweeping through Coastal Karnataka and Kerala. These opposing wind streams are creating a wind discontinuity zone stretching across parts of Karnataka, Rayalaseema, and interior Tamil Nadu.

At the same time, the seasonal north-south trough extending from Chhattisgarh through Vidarbha and Telangana is merging with this wind discontinuity over the southern peninsula. Together, these systems are expected to increase atmospheric instability over South Interior Karnataka, including Bengaluru.

As a result, converging winds and rising moisture levels are likely to trigger strong vertical cloud development over the region, leading to typical pre-monsoon thunderstorms during evening hours.

The Karnataka State Natural Disaster Monitoring Centre (KSNDMC) has also issued thunderstorm alerts for several regions of Karnataka. According to the latest forecast, thunderstorms accompanied by gusty winds reaching 40-50 kmph are likely over South Interior Karnataka between May 13 and May 16. Similar thunderstorm activity with lightning is expected over Coastal Karnataka until May 17.

Residents have been advised to remain cautious during evening hours as sudden heavy rain, lightning activity, and gusty winds may lead to traffic congestion, temporary waterlogging, and falling tree branches in some parts of Bengaluru.

Meanwhile, the India Meteorological Department (IMD) has stated that conditions are becoming favourable for the onset of the Southwest Monsoon over parts of the south Bay of Bengal, Andaman Sea, and the Andaman and Nicobar Islands around May 16-17.

The normal monsoon onset date over the Nicobar Islands is May 15, while the entire Andaman Sea is usually covered by May 20. According to IMD Director General Dr. Mrutyunjay Mohapatra, this year's monsoon progression appears to be largely on schedule.

Climatologically, the Southwest Monsoon reaches Kerala around June 1 every year. However, earlier long-range forecasts from IMD had indicated the possibility of a below-normal monsoon season for 2026, raising concerns for agriculture and water management in several parts of the country.

For Bengaluru, though, the immediate focus remains on the expected return of thunderstorms later this week, which could finally bring temporary relief from the city's recent dry and uncomfortable weather conditions.