Mumbai: One month into the monsoon season, Mumbai has registered just under a quarter of its annual rainfall, despite the southwest monsoon having now swept across the entire country ahead of schedule. The India Meteorological Department (IMD) confirmed that by June 29, the monsoon had covered the entire country, several days earlier than the forecasted timeline of early July.

However, in Mumbai, the rainfall distribution has been both uneven and intermittent. As of now, the financial capital has received 502.05 mm of rainfall, amounting to nearly 24 per cent of its annual average. The eastern suburbs have fared similarly with 483.62 mm, while the western suburbs have recorded slightly less at 449.71 mm, both regions hovering around 20 per cent of their expected yearly totals.

Higher than usual rainfall in Mumbai? Here’s what BMC data reveals

Rainfall data from the Brihanmumbai Municipal Corporation (BMC) and the IMD further indicate regional variation. Since the monsoon officially arrived on May 26, the Colaba observatory has logged 591.4 mm of rain, roughly 28 per cent of its usual 2,095 mm annual average. The Santacruz observatory, which typically measures higher volumes, has recorded 511.2 mm so far, at around 22 per cent of its 2,319 mm annual mark.

Compared to the same period last year, Mumbai’s rainfall levels are only marginally lower. In 2024, the city had recorded 507 mm by late June, 24.2 per cent of the annual average, while Santacruz had received 346.9 mm, approximately 15 per cent.

IMD’s weekly weather forecast for Mumbai

Despite the early arrival, meteorologists noted that the rain pattern has been far from consistent. Initial days saw intense spells of heavy to very heavy rain, especially in late May and early June. But these were often followed by prolonged dry spells or only light showers. While favourable synoptic conditions had helped trigger strong rainfall at the onset, experts remain cautious about interpreting these fluctuations as part of a broader seasonal trend.