Delhi records coolest May in 36 yrs as rainfall brings average temp down to 36.8 degrees

Delhi recorded its coolest May in 36 years due to excess rainfall which brought the average maximum temperature down to 36.8 degrees Celsius this time, the India Meteorological Department (IMD) said on Wednesday. The city had recorded an average maximum temperature of 36 degrees Celsius in May 1987, said Kuldeep Srivastava, the head of the regional forecasting centre of IMD.

"The average maximum temperature of 36.8 degrees Celsius in May this year is the lowest since then," he said. Delhi recorded maximum temperatures above the 40-degree mark for just nine days in May with heat wave conditions affecting some parts of the national capital for two days.

The IMD official said that Delhi's primary weather station has not recorded any heat wave in the pre-monsoon season this year. "This has happened for the first time since 2014," Srivastava said.

The weather station recorded 13 heat wave days in the pre-monsoon season last year -- nine in April and four in May. It saw just one heat wave day during this period in 2021, four in 2020 and one in 2019.

Heat wave is declared when the maximum temperature of a station reaches at least 40 degrees Celsius in the plains, 37 degrees in the coastal areas, and 30 degrees in the hilly regions, and the departure from normal is at least 4.5 notches.

May, generally the hottest month in Delhi, recorded 111 mm of rainfall this time, which is 262 per cent more than the long-term average of 30.7 mm. This is also the fourth highest rainfall in the month after 165 mm in 2008, 144.8 mm in 2021 and 129.3 mm in 2002, according to IMD data. Delhi logged more than 20 mm of rainfall in April, the highest in the month since 2017, and heat wave conditions at isolated pockets.

Meanwhile, the IMD on Wednesday said rainfall along with thunderstorm activity is likely to continue over Northwest India during the next two days. The weather agency said heat wave conditions are likely over Bihar and West Bengal during the next 3-4 days.