Mumbai Monsoon Arrives: IMD Declares Onset Amid Massive June Rain Deficit

The India Meteorological Department (IMD) officially declared the onset of the Southwest Monsoon over Mumbai today, bringing a wave of light to moderate morning showers across the island city and its suburbs.

The monsoon has advanced across the remaining areas of the central Arabian Sea, parts of Maharashtra (including Mumbai), Telangana, Odisha, Chhattisgarh, Jharkhand, and Bihar. Weather officials project the system will push further into Gujarat, Madhya Pradesh, and Uttar Pradesh over the next 2 to 4 days.

In a statement, the IMD said, "The Southwest Monsoon has further advanced into remaining parts of central Arabian Sea, some more parts of Maharashtra including Mumbai, remaining parts of Telangana & Odisha, some more parts of Chhattisgarh, Jharkhand & Bihar, today the 23rd June, 2026.

The Big Picture: A 300% Rain Deficit

While the arrival brings relief, Mumbai is starting the season from a deep visual deficit. Delayed onset and missing pre-monsoon showers have left the city parched compared to historical averages:

June Norm: 526 mm

Actual (June 1-23): 46 mm (recorded at the Santacruz observatory)

Current Status: Rain deficit exceeding 300% of the typical June average.

Morning Rain Tracks: Where it Hit Hardest

Commuters woke up to slower traffic and wet roads as early morning downpours soaked iconic spots like Marine Drive, the Bandra-Worli Sea Link, Dadar Railway Station, and Matunga.

BMC automatic weather stations tracked the heaviest bursts between 8:00 AM and 9:00 AM today:

Over the last 24 hours, total accumulation varied sharply between the coast and the suburbs, with Colaba recording 49 mm of rain while Santacruz logged just 12 mm. Residents should expect continued traffic slowdowns as the monsoon system establishes its footprint over the metro area.