This data the coastal Lake Illawarra ocean water temperature today, tomorrow and the upcoming days. Besides, you can also get information about the weather and surf forecast, as well as the data on sunrise / sunset and moonrise / moonset at a given point on any given day.
Water temperature in Lake Illawarra today is 18.2°C. Based on our historical data over a period of ten years, the warmest water in this day in Lake Illawarra was recorded in 2022 and was 17.9°C, and the coldest was recorded in 2008 at 15.5°C. Sea water temperature in Lake Illawarra is expected to drop to 17.3°C in the next 10 days. September average water temperature in Lake Illawarra is 17.3°C, the minimum temperature is 15.2°C, and the maximum is 19.5°C.
The swimming season in Lake Illawarra lasts from November to May. During those months, Lake Illawarra water temperature does not drop below 20°C and therefore suitable for comfortable swimming. The average water temperature in Lake Illawarra in winter reaches 17.9°C, in spring 18.5°C, in summer the average temperature rises to 22.2°C, and in autumn it is 21.7°C.
5 September 2025 |
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today temp |
18.2°C |
4 September 2025 |
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yesterday temp |
19.3°C |
The ocean salinity in Lake Illawarra is 35.36‰, and the average salinity of the World Ocean is 35‰.
Another important indicators for a comfortable holiday on the beach are the presence and height of the waves, as well as the speed and direction of the wind. Please find below data on the swell size for Lake Illawarra. We calculate the swell size based on the mean wave height (trough to crest) of each third highest wave. For more information on surf forecasts for the next ten days, please visit sea state forecast Lake Illawarra. Data in table shown for 5 September 2025, time in GMT 0 format (you can change the time zone on the sea state forecast page)
0-3 h | 3-6 h | 6-9 h | 9-12 h |
---|---|---|---|
5' 1" | 4' 7" | 4' 1" | 3' 10" |
1.55 m | 1.39 m | 1.25 m | 1.16 m |
12-15 h | 15-18 h | 18-21 h | 21-24 h |
---|---|---|---|
3' 8" | 3' 8" | 3' 8" | 3' 8" |
1.11 m | 1.11 m | 1.13 m | 1.12 m |
Data in a table show Lake Illawarra temperature today (5 September 2025). For more information and forecast for a few days, go to the weather forecast Lake Illawarra.
0-3 h | 3-6 h | 6-9 h | 9-12 h |
---|---|---|---|
![]() | ![]() | ![]() | ![]() |
11.4°C | 10.5°C | 9.7°C | 14.5°C |
12-15 h | 15-18 h | 18-21 h | 21-24 h |
---|---|---|---|
![]() | ![]() | ![]() | ![]() |
14.3°C | 13.8°C | 12.8°C | 12.8°C |
You may also be interested in other sections of our site for Lake Illawarra: Sunrise and Sunset, Tides
These figures shows the average, minimum and maximum monthly sea temperature in Lake Illawarra. In addition to the table values, the graph below displays of changes average surface temperature during the year. Values are calculated based on the data over the past 10 years. Using them, you can check the water temperature in Lake Illawarra on any day of this period that interests you. Click on the month link and you will see a table for each day, or alternatively you can view the temperature curve of the month and select 2 different years you want to compare, either in a table or as a curve
Month | Avr | Min | Max | |
---|---|---|---|---|
January | 22.4°C | 20.4°C | 24.7°C | warm |
Ocean water temperature in Lake Illawarra in January | ||||
February | 23.1°C | 21.3°C | 25.7°C | warm |
Ocean water temperature in Lake Illawarra in February | ||||
March | 22.9°C | 20.6°C | 24.6°C | warm |
Ocean water temperature in Lake Illawarra in March | ||||
April | 21.8°C | 19.5°C | 24.4°C | warm |
Ocean water temperature in Lake Illawarra in April | ||||
May | 20.5°C | 18°C | 22.8°C | warm |
Ocean water temperature in Lake Illawarra in May | ||||
June | 19°C | 17.1°C | 21.3°C | cold |
Ocean water temperature in Lake Illawarra in June | ||||
July | 17.7°C | 16°C | 19.9°C | cold |
Ocean water temperature in Lake Illawarra in July | ||||
August | 17°C | 15°C | 19.4°C | cold |
Ocean water temperature in Lake Illawarra in August | ||||
September | 17.3°C | 15.2°C | 19.5°C | cold |
Ocean water temperature in Lake Illawarra in September | ||||
October | 18.5°C | 16.2°C | 20.4°C | cold |
Ocean water temperature in Lake Illawarra in October | ||||
November | 19.7°C | 17.6°C | 21.9°C | cold |
Ocean water temperature in Lake Illawarra in November | ||||
December | 21°C | 18.3°C | 23.5°C | warm |
Ocean water temperature in Lake Illawarra in December |