Castlecrag — Water Temperature, Sea Conditions & Trends

Water Temperature: Daily Trends, Historical Records, and Forecast

⚠️ As of today, the minimum water temperature ranges from 60°F (15°C) to 65°F (18°C). The water is comfortable for most people, making it an ideal range for water sports enthusiasts. The temperature does not cause significant discomfort, and swimming will be pleasant for the majority. However, it's important to remember that prolonged exposure to the water can still lead to cooling, so it's essential to monitor the time spent in the water, especially for children or elderly people.

It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.

Water Temperature Chart Over the Last 30 Days

Currently, the sea water at this location is slightly cooler than average for this day in previous years.

According to our forecast, Water temperature in Castlecrag will be 18.4°C in the next 7 days. See the table below for daily data for the upcoming week.

Table of Daily Sea Temperature Data

Annual Water Temperature Overview by Month

Monthly Water Temp Ranges

30°C

25°C

20°C

15°C

10°c

5°C

0°C

Annual Water Temperature Trend

Castlecrag sits on the sheltered shorelines of Middle Harbour in northern Sydney, so its waters reflect the calm, semi-enclosed character of the estuary rather than open coastal surf. Typical seasonal water temperatures here range from around 20–25 °C in the summer months, cooling to roughly 16–18 °C in winter. Spring and autumn usually bring intermediate conditions, commonly about 17–22 °C depending on recent weather, tidal flow and depth. Local microclimates, tidal mixing and rainfall runoff can cause short-term variation, so temperatures measured in shallow coves or rock pools can be a degree or two warmer or cooler than those in deeper channels.