Moderate to dense fog may occur in some areas across the country from midnight to morning and may persist in certain places until noon, according to the Met Office.
A Bangladesh Meteorological Department (BMD) weather bulletin on Saturday said: "The temperature may fall further over the next five days."
It said: "Air navigation, inland river transport, and road communication may be temporarily disrupted due to dense fog," adding that night and day temperatures may remain nearly unchanged across the country.
The weather is expected to remain mainly dry, with a temporary partly cloudy sky in some areas, it added.
The Met Office reported that the ridge of the sub-continental high extends up to Bihar and the adjoining areas, while the seasonal low lies over the South Bay.
The maximum temperature recorded on Friday was 30.4°C at Teknaf in the Chittagong division, while the minimum temperature recorded on Saturaday was 9.9°C at Tetulia in the Rangpur division.
The Met Office further reported that the sun will set on Saturday at 5:45pm and rise at 6:39am on Sunday in the capital.