“Kolkatay brishti mane adda, cha, ar bheja rasta — in Kolkata, rain means conversation, tea, and wet streets.”
Kolkata Climate & Temperature Trends
73 years of Kolkata temperature data
Kolkata's instrumental temperature record runs back to 1951 — 73 complete years of daily observations from the India Meteorological Department, extended to the present with Open-Meteo reanalysis. The headline warming trend is modest by global standards: roughly +0.032°C per decade in mean maximum temperature.
The more revealing number is what happens after dark. Averaged across 1951–1980, Kolkata's daily minimum was 21.9°C; from 1996 onward it averages 22.4°C. Over the same span, daytime maxima averaged 31.2°C in both periods. The days have barely changed. The nights have not stopped warming — the signature of a city that increasingly holds onto its own heat.
About this data
What this page shows
Five views of the same record. The warming stripes compress 76 years into one band per year, coloured by how far that year sat above or below the 1951–1980 baseline mean of 31.2°C. The long trend chart plots annual mean maximum and minimum temperature. Extreme heat counts the days above 40°C. The seasonal radar contrasts decades against each other, and the rainfall chart groups monthly totals by decade so the monsoon's shape is visible rather than just its volume.
Where the data comes from
The base series is IMD station data for Kolkata, which runs through June 2024. Beyond that the record is continued with Open-Meteo reanalysis so the charts stay current; the two are merged into a single continuous series of 902 monthly and 76 annual records. The highest daily maximum in the record is 43°C, reached in 2024.
Limitations worth knowing
Three years are incomplete and are excluded from every trend calculation: 2023 has 334 days of observations, 2024 has 300, and 2026 is still in progress. Rainfall totals are less reliable than temperature — 2012 in particular carries an implausibly low annual total and reflects gaps in the source record rather than a real drought, so it should not be read as a dry year. A single-station record also cannot resolve the difference between neighbourhoods; the urban heat island is uneven across the city and this dataset cannot map it.
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