Heat wave-like conditions were back to torment the city on Monday with the mercury crossing the 40 degree Celsius mark at the Nungambakkam observatory for the first time this season.
In fact, the Nungambakkam weather station recorded a two-year high of 41.1 degree Celsius, while Meenambakkam touched 42.5 degrees Celsius, both four degrees above normal.
Going by the forecast, the heat wave would intensify this week as the onset of sea breeze is likely to be delayed due to strong westerlies.
Tiruttani suffered the most with mercury rising to 45.5 degrees.
K Balachandran, director, Area Cyclone Warning Centre, told Express that sea breeze, a neutralising force, has set-in late.
"Usually, it comes around 11.30 am, but today it came in at 12.45 pm because of which temperature shot up.
The sea breeze reached Meenambakkam at 1.30 pm. Same would be the case the entire week," he said.
He said the onset of Southwest monsoon over the Andaman Sea has triggered strong westerlies, which are blocking the sea breeze.
"Now, it is a tussle between sea breeze and land breeze.
If sea breeze wins, we are saved.
Otherwise, we are in for a hot weather," he said.
YEA Raj, former deputy director general of meteorology, said it is common for Chennai record high temperatures in second half of May.
Southerlies are replaced by strong westerlies leading to extreme hot weather.
Officially, the Met department issued heat wave warnings to Vellore, Krishnagiri, Kancheepuram and Tiruvallur districts.
In all, eight stations in the State breached 40 degrees mark on Monday.