The mercury on Tuesday plunged to 14°C in Purulia, Bankura and some other districts of South Bengal, around three notches below normal for this time of the year.

Free flow of cold and dry north-westerly winds from the upper reaches of the country dragged the Celsius down, said weathermen.

But this does not indicate an early onset of winter, said a Met official. It is tipped to be arrested from Thursday.

“A low pressure area has formed over the Andaman sea. It is expected to move towards the Tamil Nadu coast over the next couple of days. This will inject moisture into south Bengal,” said a Met official.

Hence, starting Thursday, minimum temperature in Purulia and Bankura would be in the range of 16-17 °C. The phase is expected to last for four-five days.

The mercury will start going down again after the system dissipates, the Met official added.