Map View of ocean currents (Top)
Hourly snapshots of predicted sea surface currents for the Rottnest Channel are shown in map view in the top figure, with colour showing current speed and direction indicated with black arrows. The colour legend shows the speed of currents in metres per second (m/s) and knots. Click on the controls at the top of the page to show a specific hour, animate the map, or advance/rewind with arrows. Time is shown in local Western Standard Time (WST) for all figures. Distance markers are shown as black dots.
Time vs. Distance ocean currents (Middle)
Current speed (colour) and direction (arrows) time series for each distance marker are shown in the second figure, with time along the horizontal axis and distance from Cottesloe along the vertical axis. This plot contains the same information as the maps above but can be used to show the direction and speed in more detail for any given HOUR / DISTANCE combination (It is not a map!). Arrows point toward the compass direction (north-south-east-west) where an object would drift following surface currents. For example, knowing their swim speed a swimmer could use this plot to estimate what currents they might expect to experience along their route at any give distance and time.
Mid-Channel weather forecast (Bottom)
The bottom plot shows predicted hourly wind and wave conditions in the middle of the Rottnest Channel (10 km marker) and aligns in time with the figure above. Wind speed is shown with the red line and grey arrows show wind direction. Wind conditions are the single most important factor for favourable swimming conditions, with wind speeds below 10 knots desirable. Keep an eye on the wind arrow direction— an abrupt change in direction (accompanied by strengthening of wind speed) often signifies the arrival of the sea breeze during summer around midday and a rapid deterioration of ocean conditions. Although the exact timing and intensity of the sea breeze is difficult to forecast, this figure can give a good indication of whether the sea breeze will arrive early or late, and should be interpreted alongside official weather forecasts provided by the Bureau of Meteorology.
This website is for informational purposes only. The information presented here are not official interpreted forecasts, but are a direct result of numerical models. The UWA coastal oceanography group and any associated parties assume no responsibility for the accuracy, completeness, timeliness or quality of the data, and do not assume any responsibility or liability for any loss, injury, damages or expenses resulting from the use or misinterpretation of information provided by the forecasts on this website.