INSTRUMENT / SEA TEMPERATURE
Rottnest Island Water Temperature
Updated Sat 14:57 (Australia/Brisbane)
Australia · Forecast updated Nov 7, 2026, 14:57 UTC
Current Sea Temperature
19.2°C
66.6°F
Cool water
Valid Nov 7, 2026, 14:57 (Australia/Brisbane). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.7°C below
The typical November average is 19.9°C (67.8°F) from the historical baseline.
Recent trend
Warming by 0.7°C
Seven-day average: 19.4°C, versus 18.7°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 or replace the snorkel forecast.
Typical Sea Temperature Over the Year
In the historical baseline for Rottnest Island, typical monthly averages range from about 18.5°C (65.3°F) in September to 22.6°C (72.7°F) in March.
Over the past 30 days, the average sea temperature in Rottnest Island has been 19.0°C.
Historical baseline (full year)
Southern Hemisphere. Summer is generally December–February; winter is June–August.
Typical monthly sea-surface temperature near Rottnest Island, calculated from hourly observations for 2022–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 21.8–22.9°C | 22.5°C / 72.5°F |
| February | 22.3–22.5°C | 22.4°C / 72.3°F |
| March | 21.9–23.3°C | 22.6°C / 72.7°F |
| April | 21.5–23.4°C | 22.4°C / 72.3°F |
| May | 21.1–22.7°C | 22.1°C / 71.8°F |
| June | 19.7–21.3°C | 20.7°C / 69.3°F |
| July | 18.4–19.9°C | 19.3°C / 66.7°F |
| August | 18.2–19.1°C | 18.7°C / 65.7°F |
| September | 18.0–18.8°C | 18.5°C / 65.3°F |
| October | 18.9–19.2°C | 19.1°C / 66.4°F |
| November | 19.6–20.1°C | 19.9°C / 67.8°F |
| December | 20.8–22.0°C | 21.4°C / 70.5°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (-32.04, 115.54). Each month is the mean of yearly monthly means; the range is the lowest and highest of those yearly monthly means. Open-Meteo methodology.
Water temperature by month
Each month uses the 2022–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Rottnest Island in January
Typical January water temperature near Rottnest Island is 22.5°C (72.5°F), with yearly monthly means from 21.8–22.9°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: December 21.4°C · February 22.4°C.
Explore Rottnest Island sea temperature in January, including swim comfort and month comparisons →
Rottnest Island in February
Typical February water temperature near Rottnest Island is 22.4°C (72.3°F), with yearly monthly means from 22.3–22.5°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: January 22.5°C · March 22.6°C.
Explore Rottnest Island sea temperature in February, including swim comfort and month comparisons →
Rottnest Island in March
Typical March water temperature near Rottnest Island is 22.6°C (72.7°F), with yearly monthly means from 21.9–23.3°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: February 22.4°C · April 22.4°C.
Explore Rottnest Island sea temperature in March, including swim comfort and month comparisons →
Rottnest Island in April
Typical April water temperature near Rottnest Island is 22.4°C (72.3°F), with yearly monthly means from 21.5–23.4°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: March 22.6°C · May 22.1°C.
Explore Rottnest Island sea temperature in April, including swim comfort and month comparisons →
Rottnest Island in May
Typical May water temperature near Rottnest Island is 22.1°C (71.8°F), with yearly monthly means from 21.1–22.7°C.
Swimming and snorkeling: mild water. A rash guard is useful; cold-sensitive snorkelers may prefer a shorty wetsuit.
Adjacent months: April 22.4°C · June 20.7°C.
Explore Rottnest Island sea temperature in May, including swim comfort and month comparisons →
Rottnest Island in June
Typical June water temperature near Rottnest Island is 20.7°C (69.3°F), with yearly monthly means from 19.7–21.3°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: May 22.1°C · July 19.3°C.
Explore Rottnest Island sea temperature in June, including swim comfort and month comparisons →
Rottnest Island in July
Typical July water temperature near Rottnest Island is 19.3°C (66.7°F), with yearly monthly means from 18.4–19.9°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: June 20.7°C · August 18.7°C.
Explore Rottnest Island sea temperature in July, including swim comfort and month comparisons →
Rottnest Island in August
Typical August water temperature near Rottnest Island is 18.7°C (65.7°F), with yearly monthly means from 18.2–19.1°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: July 19.3°C · September 18.5°C.
Explore Rottnest Island sea temperature in August, including swim comfort and month comparisons →
Rottnest Island in September
Typical September water temperature near Rottnest Island is 18.5°C (65.3°F), with yearly monthly means from 18.0–18.8°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: August 18.7°C · October 19.1°C.
Explore Rottnest Island sea temperature in September, including swim comfort and month comparisons →
Rottnest Island in October
Typical October water temperature near Rottnest Island is 19.1°C (66.4°F), with yearly monthly means from 18.9–19.2°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: September 18.5°C · November 19.9°C.
Explore Rottnest Island sea temperature in October, including swim comfort and month comparisons →
Rottnest Island in November
Typical November water temperature near Rottnest Island is 19.9°C (67.8°F), with yearly monthly means from 19.6–20.1°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: October 19.1°C · December 21.4°C.
Explore Rottnest Island sea temperature in November, including swim comfort and month comparisons →
Rottnest Island in December
Typical December water temperature near Rottnest Island is 21.4°C (70.5°F), with yearly monthly means from 20.8–22.0°C.
Swimming and snorkeling: cool water. A 3 mm shorty or full wetsuit will make longer snorkels more comfortable.
Adjacent months: November 19.9°C · January 22.5°C.
Explore Rottnest Island sea temperature in December, including swim comfort and month comparisons →
Forecast archive (growing)
These values come from hourly forecasts SnorkelForecast has stored. They cover only months with records and do not replace the historical baseline.
| 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 | 18.3°C / 64.9°F | 18.7°C / 65.7°F | 19.5°C / 67.1°F |
| September | 18.0°C / 64.4°F | 18.6°C / 65.5°F | 19.4°C / 66.9°F |
| October | 18.3°C / 64.9°F | 18.8°C / 65.9°F | 19.5°C / 67.1°F |
| November | 18.9°C / 66.0°F | 19.4°C / 66.8°F | 19.8°C / 67.6°F |
Partial coverage: 6 calendar months with records. Profile calculated from 3838 hourly forecast records across 6 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 water temperature in Rottnest Island today?
The current sea surface temperature near Rottnest Island is 19.2°C (66.6°F). Over the last 30 days, the average has been 19.0°C.
When is the water warmest in Rottnest Island?
The water is typically warmest in March, at around 22.6°C (72.7°F) in the 2022–2025 historical baseline.
When is the water coldest in Rottnest Island?
The water is typically coldest in September, at around 18.5°C (65.3°F) in the same historical baseline. 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 →