A weak southwest monsoon has prolonged summer conditions across south Bengal, with the India Meteorological Department (IMD) forecasting continued sweltering heat in the region over the next week despite the monsoon's advance into the state.

The weather department on Tuesday said the southwest monsoon remains active over the sub-Himalayan districts of West Bengal and is expected to bring heavy rainfall to north Bengal during the coming week.

In contrast, southern districts are likely to receive only isolated light showers till June 19, followed by more widespread rainfall on June 20 and 21.

According to the IMD, hot and humid conditions are expected to persist across south Bengal over the next seven days as monsoon activity remains weak in the region.

Amid the prevailing weather conditions, the state government has revised the timings of all state-run and aided schools, shifting classes to morning hours to spare students from venturing out during the oppressive heat.

The southwest monsoon had advanced into all districts of West Bengal by last week. However, weak monsoon conditions over the southern parts of the state have resulted in scant rainfall.

North Bengal continued to receive significant precipitation, with Siliguri recording the highest rainfall in the state at 96 mm during the 24-hour period ending at 8.30 am on Tuesday. Darjeeling received 27 mm of rain during the same period.

Most other parts of West Bengal reported little or no rainfall, highlighting the sharp contrast between weather conditions in the northern and southern regions of the state.