A sultry day gave way to a round of thundershowers in the afternoon in parts of Calcutta and its adjoining areas on Sunday.

The spell of rain was short but sharp, accompanied by streaks of lightning and rumblings of thunder. But it was not uniform. While some southern pockets were drenched, areas in central and north Calcutta had to be content with dark clouds and the occasional roar of thunder.

The maximum temperature touched 38 degrees, three notches above normal, on Saturday. The minimum relative humidity was around 50 per cent. For most of the day, the city felt like a cauldron.

Sunday’s clouds came to Calcutta from western districts of Bengal. The sweaty conditions are here to stay, said a Met department official.

“Sweaty conditions are typical of the monsoon because of the high moisture content in the air. But there will be a temporary phase of overcast conditions once a low-pressure area forms over the north Bay of Bengal around June 11. The system is also set to propel the monsoon into south Bengal,” said the official.

The monsoon reached north Bengal on Sunday and is expected to reach south Bengal before next weekend, the official said.

“Southwest Monsoon has advanced into most parts of Sub-Himalayan West Bengal and Sikkim today,” said an IMD statement on Sunday.