Dee Why — Water Temperature, Sea Conditions & Trends
This page provides clear and up-to-date information about water temperature for Dee Why (Australia). It includes the current water temperature, daily data for the last month presented in a simple chart, and a 7-day forecast. The page also compares today’s value with typical averages for this period, shows usual monthly ranges during the year, and lists nearby beaches with short descriptions. Local weather for the next few days and general details about Dee Why help you plan your visit and choose the best time for swimming.
Current Water Temperature
Water temperature in Dee Why in the Tasman Sea today is 18°C.
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
Water temperature in Dee Why has risen over the last week and month. Currently, the sea water temperature at this location matches the average for this day in previous years.
According to our forecast, Water temperature in Dee Why will be 18.0°C in the next 7 days. See the table below for daily data for the upcoming week.
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| AUG 30 | 17.2°C | 18.5°C | |
| AUG 31 | 17.1°C | 18.5°C | |
| SEP 1 | 17.4°C | 17.8°C | |
| SEP 2 | 17.5°C | 19.0°C | |
| SEP 3 | 17.5°C | 18.0°C | |
| SEP 4 | 17.7°C | 18.0°C | |
| SEP 5 | 17.8°C | 18.3°C | |
| SEP 6 | 17.8°C | 18.3°C | |
| SEP 7 | 17.9°C | 18.5°C | 17.9°C |
| SEP 8 | 18.8°C | 17.9°C | |
| SEP 9 | 17.8°C | 17.9°C | |
| SEP 10 | 18.0°C | 17.9°C | |
| SEP 11 | 18.3°C | 17.9°C | |
| SEP 12 | 18.5°C | 18.0°C | |
| SEP 13 | 18.0°C | 18.0°C | |
| SEP 14 | 18.0°C | 18.0°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Water temperature data for this location is gathered from various sources, including buoys and satellite sea and ocean surface maps provided by the NOAA agency. We also incorporate data from local authorities in each specific location worldwide to ensure more accurate temperature readings.
Annual Water Temperature Overview by Month
Monthly Water Temp Ranges
Annual Water Temperature Trend
Dee Why is a coastal suburb on Sydney’s Northern Beaches facing the Tasman Sea, known for a broad sandy shore and a long promenade. Sea temperatures there follow the temperate pattern typical of Sydney, with the warmest water in summer and the coolest in winter. Typical seasonal ranges are approximately 21–24 °C in summer (December to February), 18–22 °C in autumn (March to May), 15–18 °C in winter (June to August), and 16–21 °C in spring (September to November). Local conditions can vary with wind, tides and swell, so temperatures at the shoreline may feel a degree or two cooler on cloudy or windy days. The adjacent Dee Why Lagoon and rock pools offer quieter water on calm days but do not reflect ocean temperatures exactly.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 20°C | 23°C | 25°C |
| February | 22°C | 23°C | 26°C |
| March | 21°C | 23°C | 26°C |
| April | 19°C | 22°C | 25°C |
| May | 16°C | 21°C | 24°C |
| June | 15°C | 20°C | 23°C |
| July | 15°C | 19°C | 21°C |
| August | 15°C | 19°C | 20°C |
| September | 16°C | 18°C | 20°C |
| October | 16°C | 19°C | 21°C |
| November | 18°C | 20°C | 22°C |
| December | 19°C | 21°C | 25°C |
* Click on a month to view detailed water temperature data.
Dee Why: Weather Forecast
September 8
September 9
September 10
Location, Beaches & Local Information
Nearby Beaches & Facilities
Dee Why Beach
Long Reef Beach
Collaroy Rockpool
North Curl Curl Beach
Collaroy Beach
Fishermans Beach
Harbord Beach
South Curl Curl Beach
Curl Curl Beach
Swimming Conditions
Swimming at Dee Why Beach caters to a wide range of visitors, from casual beachgoers to experienced surfers. The central area is often patrolled by surf lifesavers during the warmer months and flagged swimming areas are established for safer bathing. Surf conditions can produce rips and waves suited to surfers and bodyboarders, while calmer days are good for lap-style ocean swimming or wading. Water in winter can feel brisk, so many swimmers choose wetsuits when temperatures fall into the mid‑teens Celsius. Facilities, nearby cafes and easy access from public transport make Dee Why convenient for a beach holiday, provided visitors heed safety signs and lifeguard advice.