Is it raining now in Kolkata?
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25 AugNo upcoming precipitation for the next hour.
Last update: 04:30, 25 Aug 2026
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Rain in Kolkata: What You Need to Know
Kolkata weather swings hard between a soaking monsoon and a bone-dry winter: the southwest monsoon delivers 74–83% of the city's roughly 1,675 mm annual rainfall between June and September, with July alone averaging 354 mm. A hyperlocal radar is what separates a light shower from the kind of downpour that turns Salt Lake into standing water within the hour.
Kolkata sits on flat, saucer-shaped delta terrain at an average elevation of just 20 feet, so rain has nowhere to drain quickly. Pre-monsoon Nor'westers — locally called Kal Baishakhi — bring sudden, violent thunderstorms in March–May that a standard forecast rarely catches in time, and heavy siltation in the Hooghly River has cut the channel's carrying capacity, worsening backup into low-lying wards during the main monsoon.
RainViewer's Kolkata weather map draws on India Meteorological Department radar, refreshed every 5 minutes, tracking cells as they build over the Hooghly and move across the delta. The live map shows what a forecast can't: whether Salt Lake or Behala is about to go under water in the next half hour.
Rain by Season in Kolkata
Southwest monsoon (June–September)
Kolkata's monsoon runs June through September and peaks in July at 354 mm. This is the city's most disruptive stretch — old underground drainage in North and Central Kolkata can't handle heavy bursts, and low-lying areas like Salt Lake, Behala, New Alipore, and Rajarhat see prolonged waterlogging almost every year.
Pre-monsoon transition (March–May)
March through May brings Nor'westers, sudden squally thunderstorms known locally as Kal Baishakhi, alongside temperatures over 40°C. These storms are genuinely unpredictable — they build fast and hit hard, the opposite of the steady, forecastable monsoon rain that follows, which is why outdoor plans in this window are hardest to time.
Dry season (December–February)
December is Kolkata's driest month at just 10 mm. Durga Puja, the city's biggest festival, typically falls in September–October as the monsoon withdraws, and residual rain can still disrupt outdoor pandal events even as the dry season approaches — after which the winter months bring the calmest weather of the year.
Why You Need a Rain Radar in Kolkata
Durga Puja pandal-hoppers
Pandal-hoppers heading out during Durga Puja in September–October check the radar first, since residual monsoon-withdrawal showers can still soak an evening out even as the season winds down.
Commuters in Salt Lake and Behala
Residents of Salt Lake, Behala, New Alipore, and Rajarhat — the city's most waterlogging-prone wards — track the radar during heavy monsoon spells to time a commute or school pickup before standing water builds up.
Jute mill workers along the Hooghly
Workers at the jute mills lining both banks of the Hooghly River, an industry dating to the 1870s, check the radar before moving raw jute or finished bales, since a sudden burst on top of the river's already-reduced drainage capacity can flood mill yards fast.
Port and cargo operations at Kolkata Port
Kolkata Port, which handled 63.8 million tons of cargo and remains India's largest tea-auction hub, has crews checking the radar before loading operations, since a Hooghly-side downpour can halt outdoor cargo handling with little warning.
Air travelers at Netaji Subhas Chandra Bose International Airport
Travelers heading to the airport in Dum Dum check the radar before the trip across Howrah Bridge, since a monsoon burst over the route can slow the drive from Howrah Junction significantly.
RainViewer Radar Coverage in Kolkata
RainViewer draws radar data for India from the India Meteorological Department (IMD) via mausam.imd.gov.in, updated every 5 minutes. Coverage is strongest across the Gangetic Plain, western coast, and major cities; sparser in the Himalayan foothills and remote northeast. From Kolkata, the same map covers the wider Hooghly delta, Howrah, and the approach to the Sundarbans.
Kolkata Rain Radar: Frequently Asked Questions
- Is it raining in Kolkata right now?
The only reliable answer is a live radar check — Kolkata's flat, low-lying delta terrain means a downpour in Salt Lake can leave Behala dry, and the reverse. RainViewer's hyperlocal radar draws on India Meteorological Department data and updates every 5 minutes, showing exactly where rain is falling across the city right now.
- Should I go pandal-hopping during Durga Puja?
Check the radar before heading out — Durga Puja falls right at monsoon withdrawal, and residual showers can still soak an evening even in late September or October. RainViewer shows whether a cell is clearing the route 20 to 30 minutes ahead, enough time to plan around it.
- Does rain affect the drive to Kolkata Airport?
Yes — a monsoon burst over the route to Netaji Subhas Chandra Bose International Airport in Dum Dum, especially crossing Howrah Bridge from Howrah Junction, can slow traffic significantly. Checking the radar before leaving shows whether a cell sits over the route or has already cleared.
- Does Kolkata flood when it rains?
Yes — Salt Lake, Behala, New Alipore, and Rajarhat are documented waterlogging hotspots, and Howrah and Kalighat see additional overflow risk from the Hooghly River. Old underground drainage in North and Central Kolkata is on record as unable to handle heavy bursts, so even a moderate storm can pool fast.
- When is the best time to visit Kolkata to avoid rain?
December through February is Kolkata's driest stretch, with December averaging just 10 mm, well clear of the June–September monsoon and the March–May Nor'wester season. Outdoor sightseeing around the Hooghly riverside faces the least disruption in these winter months.
- Why does it rain in one part of Kolkata but not another?
Kolkata's flat, saucer-shaped delta terrain sits at an average elevation of just 20 feet, so drainage is slow and rain pools unevenly depending on exactly where a cell passes over. That's why a city-wide Kolkata weather forecast misses what a live radar tracking cells over the Hooghly catches block by block.
- Is there a live rain radar for Kolkata?
Yes — RainViewer's hyperlocal radar for Kolkata draws on India Meteorological Department (IMD) data, refreshed every 5 minutes. It tracks cells building over the Hooghly and moving across the delta rather than giving one city-wide reading.
- Can I get a warning before rain hits Kolkata?
Yes — RainViewer's rain alert can be set for a specific spot, like a jute mill along the Hooghly or a home in Salt Lake, and it triggers before the rain arrives. That gives enough lead time to move cargo, close a mill yard, or avoid a waterlogged commute.
Track Rain in Kolkata in Real Time
Living in Salt Lake or moving jute along the Hooghly — Kolkata's flat delta terrain means monsoon rain pools fast and unevenly across the city.
A cell can build over the Hooghly and drop July-level rain on one ward while another stays dry, faster than the city's aging drains can clear it.
Your weather app said moderate rain for Kolkata today. RainViewer shows it's already flooding Salt Lake while Behala stays dry — that's the difference a jute mill supervisor along the Hooghly needs to know before moving a shipment.
Track rain in Kolkata — free Upgrade to Essential for alerts, forecasts, and full radar history
2-hour forecast in 5-minute slices
see exactly when a Salt Lake downpour is set to ease before heading out.
Rain alerts before arrival
set an alert for a jute mill along the Hooghly or a home in Behala so outdoor stock and school pickups stay ahead of the rain.
Direction arrows on the map
Kolkata's Nor'westers typically build from the northwest; direction arrows show a Kal Baishakhi storm approaching before it hits.
48 hours of radar history
check how a monsoon system has tracked over the Hooghly delta across a multi-day spell.
Multiple locations
track Salt Lake, the Hooghly mill belt, and the airport approach in Dum Dum at the same time.
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