The southwest monsoon has made its onset over parts of the south Bay of Bengal, the south Andaman Sea, the Nicobar Islands, and some areas of the north Andaman Sea, the India Meteorological Department (IMD) announced on Tuesday.

According to the IMD, widespread moderate rainfall with heavy showers at a few places occurred over the Nicobar Islands in the past 24 hours.

This followed a two-day spell of widespread rainfall with isolated to scattered heavy rainfall across the region.

In Kolkata, the local forecast for the next 24 hours predicts a partly cloudy sky with the possibility of thunderstorms accompanied by light to moderate rain towards the evening. The maximum and minimum temperatures are expected to be around 36°C and 26°C.

The city recorded a maximum temperature of 38.6°C, which is 2.8 degrees above normal, and a minimum of 23.5°C, which is 3.5 degrees below normal. Relative humidity ranged from a maximum of 98 per cent to a minimum of 35 per cent. Rainfall recorded between 11:30 pm on May 12 and 11:30 am on May 13 stood at 8.2 mm.

The weather office reported a continuous increase in the strength and depth of westerly winds over the south Bay of Bengal, the Nicobar Islands, and the Andaman Sea during the past two days.

Westerly winds at 1.5 km above mean sea level reached speeds exceeding 20 knots, with the depth of these winds extending up to 4.5 km above mean sea level in some areas.

The IMD further stated that conditions remain favourable for the southwest monsoon to advance into additional regions over the next three to four days.

These include parts of the south Arabian Sea, the Maldives and Comorin area, more parts of the south Bay of Bengal, the entire Andaman and Nicobar Islands, the remaining parts of the Andaman Sea, and portions of the central Bay of Bengal.