TodayFriday, June 12, 2026

Kolkata Weather: The Monsoon Inches Through Bengal as the City Waits at 34 Degrees

The Bay of Bengal arm is moving and the Arabian Sea arm is stalled; Kolkata sits between the season's two speeds, sweating.
June 12, 2026
Rain falling over a street in Kolkata
Rain over Kolkata in an archive image. The city has passed its usual monsoon onset date in 2026 and is waiting for the Bay of Bengal arm to cross the Gangetic plain. [Image Source: Wikimedia Commons]

KOLKATA — Both of the city’s observatories reported the same wind speed at 11:30 on Friday morning: zero. Alipore sat at 31.6 degrees Celsius in air that was 74 percent water, Dum Dum at 34.2 and drier, and not a leaf in either compound moved. A city this loud is rarely this still, and the stillness has a specific meteorological name. It is the wait.

The thing being waited for moved again on Friday. The India Meteorological Department’s June 12 bulletin recorded the southwest monsoon advancing into some more parts of West Bengal and Bihar, the third push through the state in four days. The line entered sub-Himalayan Bengal on June 9, took more of the state on June 11, and is now working down toward the Gangetic plain that holds the city.

Kolkata is now the last of India’s six biggest metros without its season resolved, and it is past its appointment. The agency’s climatological maps put the monsoon’s normal arrival over the city at around June 10. What arrival means here is concrete: the humidity that builds for weeks finally converts into rain, the temperature loses its afternoon spike, and the city begins the annual examination of its pumps and drains that no Kolkata June has ever fully passed.

The season is running at two speeds, and Kolkata is standing in front of the faster one. The Bay of Bengal arm has been the year’s workhorse, soaking the northeast ahead of schedule and now stepping through Bengal and Bihar almost daily. The Arabian Sea arm, the one Mumbai depends on, has stalled short of Maharashtra entirely, leaving that coast past its own date and dry. Two cities, two arms, one calendar neither controls.

Two days ago this newspaper’s national weather roundup called Kolkata the odd city out, humid and waiting while Delhi got storms and the south got the season itself. The label still holds, but the margin is shrinking by the bulletin. Some more parts of West Bengal is the agency’s deliberately unmapped phrase, and somewhere inside it the line is approaching a city of 15 million that can feel it coming in the weight of the air.

Dark monsoon clouds building in the sky
Monsoon clouds build in an archive image. The Bay of Bengal arm of the 2026 season has pushed through Bengal three times in four days, by the IMD’s bulletins. [Image Source: Wikimedia Commons]

Arrival, when it comes, tends to follow a known script on this side of the country. The first sign is rarely the steady rain itself but the evening thunderstorm that breaks the heat like a dropped plate, the kind the Kalbaisakhi season usually supplies in April and May and mostly withheld this year. After the first two or three of those, the regime settles in, and the rain stops being an event and becomes the climate.

What the IMD has not done is declare onset over Kolkata or name its day. The bulletin language maps the advance by region, not by city, and the agency will not certify arrival until its rainfall criteria are met at the stations now reporting calm. There are no rainfall totals in the city to report yet, and no alert tier either, which in a week when Delhi sits under red and Bengaluru under yellow is its own kind of forecast.

So the city does the only thing a city can do with an appointment the sky keeps rescheduling. It checks the bulletin, reads the words some more parts, and looks south past the river, where the season is now days away by any measure and hours away by hope. At both observatories the anemometers hold at zero. In Kolkata in mid-June, that number is not the absence of weather. It is the weather, right up until the moment it breaks.

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The Eastern Herald’s Editorial Board validates, writes, and publishes the stories under this byline. That includes editorials, news stories, letters to the editor, and multimedia features on easternherald.com.

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