As someone without a background in climate science, I have in general found research and writing on warming to be fairly impenetrable. One of the principles that we follow at Data For India is to minimise the use of modelled data because it places a layer between the data and people, and we'd rather work with the raw data directly. So much of the writing on climate is built around modelled data, adding to the impenetrability. All of which has made our new climate writing, particularly around temperatures, come as a relief to me at least.
For her work, my colleague Juhi Chatterjee directly used India Meteorological Department (IMD) data on recorded temperatures from 1901 onwards to show us some big shifts. The IMD aggregates observations from a network of weather stations distributed across the country, Juhi explains. Daily observations from these stations undergo quality control and are then interpolated to a regular grid covering India. For each grid cell, daily and monthly averages are computed. The national value is derived by estimating the area‑weighted average of all grid‑cell values, ensuring that larger regions contribute proportionally more to the national average.
Using this data, she finds that from 1901 to 2024, the mean temperature for India increased by approximately 0.9°C. For context, the Intergovernmental Panel on Climate Change (IPCC) estimates that each additional 0.1°C increases the intensity and frequency of heatwaves, rainfall extremes and droughts.
You can see that warming increased rapidly from the 1990s onwards, and that the past decade (2015-2025) was the hottest on record with 2024 standing out as the warmest year in over a century.
There are a number of important details in the piece - the fact that minimum temperatures rose faster, for instance, and that night-time temperatures rose more relative to the baseline.
For policy and planning, I can see why climate modelling is essential. But to simply get on the page about what warming in India looks like and what the big shifts have been, I am thankful for this basic, essential work.
