The high relative humidity will affect coastal and adjoining districts, say experts. “Since the relative humidity is hovering between 50 per cent and 90 per cent over the coastal and adjoining districts, the actual air temperature is likely to be perceived more than the normal by 4 to 5 degrees Celsius,” said an expert from the Regional Meteorological Department, Chennai. This trend is expected to continue until Thursday.

Meanwhile, Chennai saw a maximum temperature of 35.9 degrees at Nungambakkam and 37.6 degrees at Meenambakkam. However, the humidity at each place respectively was 68 per cent and 58 per cent, with the actual maximum temperature departure being under 1 degree for both the places.

Until Sunday, thunderstorms are expected in Ghat districts. “Light to moderate rain is likely to occur at isolated places over Western Ghat districts. Light rain is also likely to occur at isolated places over interior Tamil Nadu until May 2. It is probable that dry weather is likely to prevail over the rest of Tamil Nadu, Puducherry and Karaikal area,” said a forecast from the RMC.

However, only trace rainfall was recorded across the state on Wednesday, according to official records.