Mosman – current water temperature and swimming conditions

Water Temperature in Mosman: Daily Trends, Historical Records, and Forecast

✅ This water feels mild to warm and is comfortable for the majority of swimmers. Swimming is enjoyable, though longer stays may feel cooler for some people, especially in windy conditions. These temperatures are well suited to family outings and active swimming, particularly on warm days.

It’s important to note that these swimming tips and recommendations apply only in settled weather. When air temperatures drop below 20°C — and sometimes even below 25°C — swimming can feel uncomfortable, even when water temperatures are relatively high.

Water Temperature Over the Last 30 Days

While water temperatures in Mosman declined overall during the past month, they have shown a noticeable rebound over the last week.

According to our forecast, Sea water temperature in Mosman will be 21.3°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

Mosman sits on Sydney’s Lower North Shore, surrounded by harbour waters that connect to the Tasman Sea, and this sheltered setting has a strong influence on local water temperatures. In summer, the water usually warms to around 22–25 °C, which feels comfortable for long swims and casual dips. Autumn often holds onto that warmth, with temperatures commonly between 20–23 °C, while spring is cooler at roughly 18–21 °C as the harbour gradually warms after winter. During winter, water temperatures typically drop to about 16–18 °C, which can feel cool but is still manageable for short swims, especially on clear, sunny days.