Rottnest Island Sea Temperature
Updated Sat 10:39 (Australia/Brisbane)
Australia · Forecast updated Aug 8, 2026, 10:39 UTC
Current Sea Temperature
19.2°C
66.6°F
Cool water
Versus this month's average
Close to average
The August average in our archive is 19.1°C (66.3°F).
Recent trend
Holding fairly steady
Seven-day average: 19.2°C, versus 19.4°C in the prior seven days.
What to wear
Cool water
A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions.
Sea Surface Temperature Over the Year
In the data collected for Rottnest Island, monthly averages range from about 19.1°C (66.3°F) in August to 20.2°C (68.4°F) in June.
Over the past 30 days, the average sea temperature in Rottnest Island has been 19.3°C.
Monthly Water Temperature Averages
| Month | Min | Average | Max |
|---|---|---|---|
| June | 19.3°C / 66.7°F | 20.2°C / 68.4°F | 21.6°C / 70.9°F |
| July | 18.6°C / 65.5°F | 19.3°C / 66.8°F | 20.3°C / 68.5°F |
| August | 18.5°C / 65.3°F | 19.1°C / 66.3°F | 19.5°C / 67.1°F |
Profile calculated from 1650 hourly forecast records across 3 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Rottnest Island
Island off Perth with sheltered bays, seagrass meadows and shipwreck snorkel trails.
- Area
- Western Australia
Rottnest Island Water Temperature: Common Questions
What is the sea temperature in Rottnest Island today?
The current sea surface temperature in Rottnest Island is 19.2°C. Over the last 30 days, the average has been 19.3°C.
When is the water warmest in Rottnest Island?
The warmest monthly average in the Rottnest Island archive is June, at around 20.2°C (68.4°F).
When is the water coldest in Rottnest Island?
The coldest monthly average in the archive is August, at around 19.1°C (66.3°F). A wetsuit is usually recommended during this period.
Can you swim in Rottnest Island today?
The water is 19.2°C. It may feel cool, but a wetsuit or short swims can help.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Rottnest Island.
View Snorkel Forecast →