The principal time of inflow of North Sea water is during spring and summer.
In the sense of "flowing water," the word is applied to the inflow of the tide, as opposed to "ebb."
The inflow to the deep basins is intermittent, probably with a long period of flux and reflux.
Therefore the inflow waxes and wanes from season to season throughout the year, but it also varies in the same season in different years.
Where the evaporation is at a minimum, the inflow of rivers from a large continental area and the precipitation from the atmosphere at a maximum, there is necessarily the greatest dilution of the sea-water, the Baltic and the Arctic Sea being conspicuous examples.