There are many excellent sources of weather forecast and observations available online, here is a selection of the most popular one in Australia:

• Bureau Of Meteorology – marine forecasts [website]
• BoM 7 day Marine forecast
• BoM Ocean Temperature and Currents
• Seabreeze – 7 day graphical forecasts, not just for surfing… [website]
• Willyweather – comprehensive local weather site, worth exploring [website]
• Passage Weather – free 7 day international  forecasts (incl SE Australia) [website]

Paid 7 day forecasts (free trials and short term forecasts available):
• Buoyweather [website],
• PredictWind [website],
• Wind Guru website