Dee Why – current water temperature and swimming conditions

Water Temperature in Dee Why: Daily Trends, Historical Records, and Forecast

⚠️ Water in this range feels cool but still manageable for many swimmers. Short to moderate swims are comfortable, especially in warm weather. Some people may prefer a wetsuit for longer stays, particularly when swimming actively or outside peak summer conditions.

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

Water temperatures in Dee Why have been gradually cooling over the past month, with a further drop recorded during the last week.

According to our forecast, Sea water temperature in Dee Why will be 18.9°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

Dee Why, on Sydney’s Northern Beaches, faces the open Tasman Sea and enjoys water temperatures that make swimming appealing for much of the year. In summer, the ocean is at its warmest, usually around 22–26 °C, which feels comfortable for long swims and regular dips. Autumn brings a gradual cool-down to roughly 20–23 °C, still pleasant for most swimmers. Winter is cooler but far from harsh, with sea temperatures generally between 16–20 °C. Spring sees a steady warm-up from about 18 °C into the low twenties as air temperatures rise and conditions become more settled.