Heron Island Sea Temperature
Updated Sat 16:40 (Australia/Brisbane)
Australia · Forecast updated Sep 5, 2026, 16:40 UTC
Current Sea Temperature
21.9°C
71.4°F
Cool water
Versus this month's average
Close to average
The September average in our archive is 21.9°C (71.4°F).
Recent trend
Holding fairly steady
Seven-day average: 21.4°C, versus 21.5°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 Heron Island, monthly averages range from about 21.0°C (69.8°F) in July to 22.2°C (71.9°F) in June.
Over the past 30 days, the average sea temperature in Heron Island has been 21.2°C.
Monthly Water Temperature Averages
Southern Hemisphere. Summer is generally December–February; winter is June–August.
| Month | Min | Average | Max |
|---|---|---|---|
| June | 21.0°C / 69.8°F | 22.2°C / 71.9°F | 23.2°C / 73.8°F |
| July | 20.2°C / 68.4°F | 21.0°C / 69.8°F | 22.4°C / 72.3°F |
| August | 20.3°C / 68.5°F | 21.0°C / 69.8°F | 22.3°C / 72.1°F |
| September | 20.9°C / 69.6°F | 21.9°C / 71.4°F | 22.7°C / 72.9°F |
Profile calculated from 2329 hourly forecast records across 4 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Heron Island
Coral cay sitting right on the Great Barrier Reef with reef accessible from the beach.
- Area
- Queensland
Heron Island Water Temperature: Common Questions
What is the sea temperature in Heron Island today?
The current sea surface temperature in Heron Island is 21.9°C. Over the last 30 days, the average has been 21.2°C.
When is the water warmest in Heron Island?
The warmest monthly average in the Heron Island archive is June, at around 22.2°C (71.9°F).
When is the water coldest in Heron Island?
The coldest monthly average in the archive is July, at around 21.0°C (69.8°F).
Can you swim in Heron Island today?
At 21.9°C, the water is usually comfortable for swimming and snorkeling.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Heron Island.
View Snorkel Forecast →