A monograph titled ‘Heat and Cold waves in India: Process and Predictability’ published recently by the India Meteorological Department (IMD), Indian Institute of Tropical Meteorology, Pune, and Ministry of Earth Sciences, indicated that it was not a one-off instance. The report analysing data since 1960 indicated that Gujarat had recorded a significant drop in cold waves and rise in heat waves.
According to the report, seven weather stations – Bhuj, Deesa, Rajkot, Ahmedabad, Veraval, Surat, and Dwarka – recorded a significant drop in cold wave days (CWD) from 1970 to 2020. On the other hand, two stations – Bhuj and Rajkot – recorded significant rise in heat wave days (HWD), Deesa, Veraval and Surat logged rise, and Ahmedabad drop in HWD based on data from 1961 to 2020.
The criteria for heat wave and cold wave are at least 40 degrees celsius and 10 degrees celsius temperatures respectively, and deviation of up to 5 degrees for two consecutive days at more than one weather station.
In terms of frequency of heat waves, Rajkot and Deesa recorded a significant rise, whereas Bhuj recorded a rise.