May records highest rainfall since 1901; Delhi remained unusually cool

Hindustan Times

03-06-2025

New Delhi: The month of May was unusually cooler this year, with average daytime temperatures recording the seventh lowest for the month since 1901 and the lowest in the last four years, according to the India Meteorological Department's temperature and rainfall report for May.
Night-time temperatures, or minimum temperatures, were also on the lower side this May, which recorded the 59th lowest average minimum temperatures for the month since 1901.
'Over India, the average maximum temperature (35.08 degree Celsius) was 7th lowest and average minimum temperature (24.07 degree Celsius) was 59th lowest since 1901. Mean temperature (29.57 degree Celsius) was the 19th lowest since 1901,' the IMD report said.
The report also highlighted that the average rainfall across the country in May, recorded at 126.7 mm (106.4% of the long period average), was the highest for the month since 1901, when the temperatures first began recording. This May also recorded the highest number of heavy (64.5 to 115.5 mm) rain events at 1,053; very heavy (115.6 to 204.5 mm) rain events at 262; and extremely heavy (more than 204.5 mm) rain events at 39, in the past five years, barring 2021, when the number of extremely heavy rain events was higher at 42.
OP Sreejith, scientist and head, Climate Monitoring and Prediction Group, IMD, cited long spells of 'overcast skies and wet conditions' behind the unusually cooler month of May this year. 'There are three main reasons for such unusual rains. First, Monsoon arrived early. Secondly, two depressions formed over Arabian Sea and Bay of Bengal; and third, more Western Disturbances (WDs) impacted northern India,' Sreejith said.
According to IMD data, the coolest May was recorded in 1917, when the average maximum temperature across the country was logged at 33.09°C. The next coolest May was recorded in 1933, with the average daytime temperature at 34.10°C, followed by 34.88°C in 1977, 34.93°C in 2021, 34.98°C in 1920, and 35.05°C in 1971.
Over Central India, the average day temperature the previous month stood at 36.63 degree Celsius, the third lowest since 1901, while the average minimum temperature (25.14 degree Celsius) was the 12th lowest since 1901. Mean temperature (30.89 degree C) was the 3rd lowest since 1901, according to IMD.
HT has earlier reported that May has been unusual for northwest India, particularly because of persistence of slow-moving western disturbances over the region. WDs are cyclones originating in the Mediterranean Sea which move east and bring winter rain to the northwest India. The impact of WDs is felt normally during December, January and February, but this year they have been active till late May. A persistence of WDs is normally deemed unfavourable for the monsoon, according to experts.
'WDs are persisting till summer this year. Monsoon has not progressed to NW India yet and hence we cannot say whether it will interact with these WDs. One of the main reasons we are seeing sudden, intense thunderstorm activity over NW India is the unusual persistence of these WDs,' M Mohapatra, director general, IMD, said last week.
The northern limit of the Southwest Monsoon continues to pass through Mumbai, Ahilyanagar, Adilabad, Bhawanipatna, Puri, Sandhead Island. It has not progressed since last week, IMD said.