India, March 27 -- 40degC is an important threshold for summer in India. With global warming and deepening climate crisis, what is happening to this threshold on India's temperature map? An HT analysis of the India Meteorological Department's (IMD) gridded database shows that the 40degC heat threshold now arrives earlier in most places and lasts longer , although there is no significant change in its geographical spread. Here is a detailed analysis of the data.

Over 90% area that breaches the 40degC threshold does so earlier now

For 91.2% of the area that crosses the 40degC threshold, the first day of the breach in the decade 2015-2024 was earlier than during 1981-2010, the period which IMD averages to find the "normal" temperature of a...