Monday was a dry July 21 in Calcutta, unlike the past couple of years, but another rainy spell is incoming, the Met office said.

A low-pressure area is likely to take shape over the north Bay of Bengal mid-week. The system and the favourable position of the monsoon trough are expected to trigger widespread rain across Bengal, according to the forecast.

A Met bulletin predicted heavy rain in several places between July 23 and 27. Calcutta does not figure on the list, but the city may get heavy rain, said a Met official.

“A low-pressure area is likely to form over the north Bay of Bengal around July 24. Rainfall activity is likely to increase with isolated heavy to very-heavy rainfall very likely in south Bengal between July 23 and 27,” the bulletin said.

The official forecast for Calcutta for the next couple of days is “generally cloudy sky with light rain”.