The southwest monsoon withdrew from Mumbai on 10th October 2025. Post-withdrawal, Mumbai generally dries up, and showers, if any, are very occasional. More often, any weather system over the Arabian Sea, in proximity to the west coast, triggers rain and thundershowers. As it is, the normal date of monsoon retreat is 8th October, and the recoiling monsoon usually leaves behind one or two decent spells of showers over the city and suburbs. The normal rainfall for October is 91.3 mm. When the withdrawal happens early or on time, the city often misses the mark. Yet, any post-monsoon storm in the Arabian Sea raises the chances of unseasonal rains for the Konkan coast in general and Mumbai in particular. One such situation is building up more effectively around the weekend and the start of next week.

There is a cyclonic circulation over the southeast Arabian Sea and the neighbouring equatorial region in the mid-levels of the atmosphere. This system has an extension of a trough extending northward along the Western Ghats up to Konkan and Goa. The cyclonic circulation is likely to percolate into the lower levels and become more marked. Under its influence, a low-pressure area is likely to form over the southeast Arabian Sea and the Lakshadweep region around the upcoming weekend.

The weather system is expected to strengthen, possibly into a storm, while over the deep sea. In any case, the system will keep a safe distance from the Konkan coast, and no potent threat is envisaged for the coastal town of Mumbai and its suburbs. Yet, the weather system will be strong enough to alter the wind pattern off and along the coast and over the open waters of the Arabian Sea. Moist easterly and southeasterly winds are likely to sweep the entire coastline during this week and spill over into the next one as well. The wind stream will become stronger when the weather system reaches the middle of the sea on 20th and 21st October. The storm will head toward the African coast without posing any danger to the Indian coastline.

Under the influence of this system, a partly cloudy sky is likely over Mumbai. Very light rainfall can be expected between 16th and 19th October. Showers will be fleeting and patchy. The frequency and coverage of these showers will increase next week, right from the beginning and lasting till the weekend. Once the storm gets closer to the African coast, weather conditions will ease out and return to normal from 26th October onwards.