Tides and Currents
High water springs 1.6 m. High water neaps 1.3 m.
When the river is not affected by fresh water, currents run at a maximum rate of 1.5 knots.
After considerable heavy rain in the Hunter River catchment the Ebb tide induced current may exceed 3.0 knots.
Wind and Sea
The entrance is subject to swell conditions and on an average of 3 - 5 days a year the port may be closed due to weather.
During Summer, afternoon NE sea breezes up to 25.0 knots are regular. Approximately every 3 days, the passage of a cold front will be associated with fresh S sector winds. Occasionally, at the end of a hot day, a Southerly ‘Buster’ with gale force winds can persist for several hours.
During Autumn, there is an increase in cyclonic depressions (known locally as the ‘East Coast Low’) in the central Tasman Sea. These produce gale force winds (that generally persist for several days) causing rapid formation of significant swells.
During Winter, W sector winds are associated with fast moving depressions and cold fronts consisting of polar maritime air that often produce rain. Deep Lows in the Tasman Sea are a regular feature. Occasionally lows form close to the NSW coast and cause extreme weather.
Early Spring is often characterised by periods of strong NW winds. The East Coast Low may still form in the Tasman Sea
(as mentioned above). Later in Spring the W sector winds ease with the warmer weather and light afternoon NE sea breezes commence.
When conditions suit at night, radiation fog can form over low-lying areas to the N and W of the port. Light katabatic NW winds move the fog over the port area and may remain until mid morning.