Even as October winds down, Mumbai has continued to wake up to overcast skies and intermittent showers surprising many who assumed the monsoon was over. The India Meteorological Department (IMD) formally declared the withdrawal of the southwest monsoon from Mumbai on Oct. 10, 2025. So why is there a wet spell now?
Speaking to Mid-Day, IMD scientist B Nitha Sashidharan explained what's really driving the late-season showers. According to Sashidharan, the current rains are not a spillover from the retreating monsoon. Instead, they are linked to a depression over the East-Central Arabian Sea, which has channeled the moisture into the Mumbai region and that's why there are thundershowers still happening.
How IMD decides when the monsoon is "over"
Withdrawal isn't declared on a whim. IMD looks for three key signals:
Cessation of rainfall over the area.
Establishment of an anticyclone in the lower troposphere.
A marked drop in moisture content.
All three conditions were met for Mumbai by Oct. 10, which is why the recent rain is being treated as post-monsoon weather, not a reversal of withdrawal.
Why Mumbai Showers Feel So Intense
Over the past two–three days, Mumbai and neighbouring areas have seen thundershowers with short, sharp bursts which is slightly different from the longer, persistent monsoon rains.
IMD's daily forecast placed the city under a yellow alert and cautioned of intense spells up to 60 mm per hour, accompanied by thunder.
These convective cells build quickly and dump heavy rain in brief windows, explaining the sudden waterlogging despite relatively short durations.
Local weatherman Rushikesh Agre on his X handle delivered a real-time weather alert for heavy to intense rains hitting South Mumbai around 5 p.m. on Oct. 28, with radar imagery showing a strong precipitation band approaching from the Arabian Sea.
The dedicated tracker of Mumbai's meteorology aligns with IMD reports of unusual late-October showers driven by post-monsoon moisture and a low-pressure system, exceeding the typical 80 mm monthly average.
5 PM.. ⚡ Rainy evening ahead for Mumbai! Heavy to intense rains ahead for South Mumbai ⛈️
October 28, 2025
Western suburbs & central areas will also get heavy rain next few hours, stay tuned for live updates #MumbaiRains pic.twitter.com/rHzLBUqgMXA depression over the Arabian Sea brought unseasonal showers to Mumbai on Tuesday evening, with the weather department forecasting intermittent rainfall over the next 48 hours.
The Colaba observatory recorded 11 mm of rainfall between 8.30 a.m. and 5.30 p.m., while Santacruz observatory recorded no rainfall, an official from the Regional Meteorological Centre (RMC) said.
The weather system over the Arabian Sea is expected to bring intermittent showers to the city over the next 48 hours, an RMC official said.
Hence, Mumbai's late-October rain isn't a monsoon anomaly—it's a separate, post-monsoon weather system tapping Arabian Sea moisture and firing up thunderstorm-driven bursts. With IMD flagging short, heavy spells, Mumbaikars should plan for sudden downpours even as the calendar edges toward November.
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