Month-specific sea-surface temperature · Australia

Jervis Bay Sea Temperature in September

17.8°C

64.0°F

In September, sea-surface temperature near Jervis Bay has a historical monthly average of 17.8°C. This is not the reading for any particular holiday date.

Across 2023–2025, the lowest and highest yearly September monthly means were 17.1–18.5°C. These are not daily extremes.

Previous month

August · 17.3°C

Change into September: +0.5°C

Next month

October · 18.8°C

Change into next month: +1.0°C

Can you swim or snorkel in Jervis Bay in September?

At 17.8°C our temperature-only guide describes the water as cold water. Comfort depends on your cold tolerance, immersion time and wind. A historical average cannot determine whether conditions are safe on any given day.

Do you need a wetsuit?

Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.

Which beach should you choose?

Look for a beach sheltered from the actual forecast waves and wind on your visit. Exposure, currents and entry conditions vary even where water temperatures are similar. Follow local warnings.

Check the current waves, wind and snorkeling forecast →

A live forecast does not predict a future September. Check again close to your trip.

Waves and wind: recorded-model conditions for September

These figures come from a separately modelled, date-specific wind/wave backfill, not the NOAA SST series. A single observed season is not a climatological likelihood or a guarantee of safe conditions.

Morning calm hours

Afternoon calm hours

Historical coverage

September 2026

30 valid days

A “calm hour” meets fixed modelled wave/wind thresholds; neither visibility nor local currents, entry conditions or actual beach safety is measured here. Periods may differ by coast.

Jervis Bay Sea Temperature: All 12 Months

Choose a month for available historical evidence, month comparisons and swim guidance. Missing history is clearly marked and never presented as a long-term normal.

January 21.3°C February 22.7°C March 22.3°C April 21.8°C May 20.7°C June 19.0°C July 17.4°C August 17.3°C September 17.8°C October 18.8°C November 19.0°C December 20.3°C

Data source and limitations

Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature; 2023–2025. Marine model grid near -35.10, 150.73. Based on 3 yearly monthly means and 2160 recorded samples. Source methodology.

Modelled sea-surface temperatures do not establish underwater visibility, wildlife, calm currents or safe entry.