Kolkata is expected to welcome the southwest monsoon within the next three days, with two cyclonic circulations over the Bay of Bengal pushing rain-bearing clouds towards coastal Bengal, according to the Regional Meteorological Centre (RMC). The city and the broader south Bengal region are set to receive widespread rainfall starting Monday, intensifying by midweek.
Officials from the India Meteorological Department (IMD) said that while the monsoon traditionally arrives in Kolkata around June 10, the current systems suggest a delayed but imminent onset. “If rainfall from the cyclonic circulations continues, monsoon currents should reach south Bengal, including Kolkata, within three days,” said a senior RMC official. From Tuesday onwards, the rain activity is expected to expand, drenching most of south Bengal as the monsoon currents gain strength.
Heavy showers are forecast for East Midnapore and South 24 Parganas on Monday, with light to moderate spells in Kolkata and neighbouring districts. The meteorological bulletin released by RMC noted that the atmospheric and oceanic conditions are becoming increasingly favourable for the advancement of the southwest monsoon over parts of West Bengal, Jharkhand, and Bihar during the next 72 hours.
Currently, a cyclonic circulation that had formed over south Bangladesh and the adjoining North Bay of Bengal has shifted and now lies over the Northwest Bay of Bengal and surrounding areas. This system extends vertically between 3.1 km and 7.6 km above mean sea level and is tilting south-westward with height, increasing the likelihood of moisture-laden winds moving inland. Additionally, a second cyclonic circulation over the West Central Bay of Bengal near the Andhra Pradesh coast has now merged with the first.
A trough, which had developed over East Madhya Pradesh, stretches across Chhattisgarh, Jharkhand, and Gangetic West Bengal before reaching Bangladesh. This trough extends up to 1.5 km above mean sea level, also tilting south-westward with height—a configuration typically associated with pre-monsoon intensification. According to meteorologists, the weak and stagnant monsoon currents that had lingered over the region for over a week are now gaining momentum.
As rainfall picks up in the next 48 to 72 hours, urban planners and civic bodies in Kolkata are expected to activate monsoon preparedness protocols, including drainage checks and flood-risk mitigation, especially in low-lying areas prone to waterlogging. The expected monsoon onset is seen as timely relief for residents suffering under prolonged humidity and high temperatures, while also being crucial for the agricultural calendar across Bengal.
