The mean yearly precipitation observed is of 1316 mm (51.8).
The dominant winds come from the north, north-east and north-west.
The average sea temperature (as observed in Neum) ranges from 13 °C (55 °F) in January to 28 °C (82 °F) in July and August.
The bay is under the intermittent influence of fresh water from the river Neretva, naturally more pronounced in its outer and central parts and during the season of high discharge and/or strong Western winds. 
Yet, the dominant influence is that of abundant submarine springs of fresh water from the surrounding coast.
According to the concentration in nutrient salts and the quantity of phytoplancton, the bay may be characterized as a naturally mildly eutrophic system.
The bay hosts the largest oyster cultivation facilities in the Adriatic. Mussels are also part of the mariculture. The favorable hydrological conditions for seashell cultivation have been recognized since Ancient times: remnants of oyster farming dating back to the Roman Empire have been found in the area; the first written documents on oyster gathering there are from the 16th century, and those which relate to seashell culture from the 17th, as recorded in the Republic of Dubrovnik.
In the 1980s, the bay's production was at an average of up to two million of oysters and 3,000 tonnes of mussels, accounting for 60% of the Croatian oyster production. The facilities were gravely damaged during the Croatian War of Independence.