The peak summer period has come to a close. But many parts of the state are in the grip of severe heat. Though thundershowers in the evening may bring some respite, the hot weather is likely to persist for a few days even in June.
Additional Director General of Meteorology, Chennai, S. Balachandran said the state has experienced a normal summer (March-May), with temperatures being close to the average. In May, nearly 60% of the state’s weather stations recorded temperatures slightly above normal, between 1 degree and 2.5 degrees Celsius. The average monthly temperature in many districts ranged between 33-38 degree Celsius.
The average maximum temperature for May in Vellore district reached a maximum of 38.3°C. A heatwave-like situation had prevailed in the district as the mercury level climbed above the 40-degree mark in 11 days. Meenambakkam in Chennai was the second hottest place in May with eight hot days when the temperature crossed 40 degrees Celsius. He said that while Karur had a hot day for six days, the day temperature in Chennai’s Nungambakkam went above 40 degrees for five days. Meenambakkam also holds the record for maximum temperature reaching 42.7 °C on 17 May.
The trough moving towards South Tamil Nadu may bring light rains and provide temporary relief. However, it cannot guarantee drastic changes in temperature levels. The Met department has predicted heavy rain in six districts including Tirupattur, Erode and Salem on Thursday.
“Due to the moisture ahead of the onset of southwest monsoon, there will be thunderstorms in parts of the state including Chennai this week. A weather system over the Arabian Sea will also affect the wet weather in some districts,” Mr Balachandran said.
Palayamkottai and Vellore recorded maximum temperature of 39.1 degree Celsius on Wednesday. Chennai recorded a temperature of 37.8 degrees Celsius, near normal. The end of May may not mean the end of summer. The mercury level will remain around 37-38 degree Celsius in some areas till June 15 and will start falling gradually. He said there have been occasions when Chennai recorded a temperature of 40 degree Celsius in June as well.
Mr Balachandran said that there could be variation in the days of summer and local parameters like sea breeze also influenced the weather. Last year there were no hot days in Chennai. Similarly, the average number of hot days (when the temperature crosses 40 °C) has also changed over the past two decades. While 8.3 warm days were recorded in May in 2001-2010, it decreased to 5.3 warm days in May between 2011 and 2020.