Kolkata · Best Time to Visit

The clear answer is October to March, the cool dry window that also happens to coincide with Kolkata's festival season. The city has a tropical climate with a long hot, humid summer and a heavy monsoon, so the difference between the right months and the wrong ones is substantial. The figures below follow climate normals of the type compiled by the India Meteorological Department (IMD); treat them as typical averages rather than a forecast for your specific dates.

Summer (March–May) is hot and increasingly humid. Daytime maximums climb through the 30s Celsius, and in the driest spells before the rains temperatures can push past 40°C, made harder to bear by the moisture-laden delta air. Late-afternoon thunderstorms — the famous Nor'westers, known locally as Kalbaishakhi — can arrive with dramatic squalls that briefly cool things down. If you travel in these months, plan sightseeing for the early morning and evening and retreat from the mid-day sun.

Monsoon (June–September) brings the South-West monsoon off the Bay of Bengal, and it supplies the great bulk of the city's rainfall — Kolkata's annual total is on the order of 1,700 millimetres, with July and August the wettest months. Expect high humidity, heavy downpours and the risk of waterlogging in low-lying streets after sustained rain. The city is green and atmospheric, and crowds are thinner, but you should build slack into your plans and carry rain protection. This is a workable shoulder season for flexible travellers rather than a first choice.

Autumn and winter (October–March) is the ideal window and the reason most visitors come now. From October the monsoon withdraws, humidity eases, and the weather turns pleasant — comfortable, sunny days and cooler evenings. December and January are the coolest and most agreeable months, with mild days generally in the 20s Celsius and cool nights that can dip lower, so pack a light layer for the evenings. The light is clear and flattering for the city's monuments and riverfront.

The great bonus of this season is the festival calendar. Durga Puja, the city's defining event, usually falls in late September or October and is the single most spectacular time to be in Kolkata (see the culture section). It is followed within weeks by Kali Puja/Diwali and then, in the cool of the year's end, by Christmas around Park Street, which the city celebrates with unusual enthusiasm, and the Kolkata Book Fair in the new year. Timing a visit to catch Durga Puja is the ultimate Kolkata experience, but be warned that the city fills to bursting, accommodation is scarce and expensive, and the crowds around the pandals (temporary pavilions) are immense — book far ahead and pace yourself.

When not to go, purely for comfort: the peak of the pre-monsoon heat in April–May, and the wettest stretch of July–August, when waterlogging can disrupt plans. Everything in the cool October-to-March window is fair game.