Australia — Sea Water Temperature and Annual Ranges

Sea Water Temperature Along the Coast

Places with the Warmest Sea Water Today

The Most Popular Seaside Places

Coastal Seas and Oceans

Water Temperature and Swimming Overview

Water Temperature Trends

Australia’s coastline spans tropical to cool temperate waters, so sea temperatures vary widely by region and season. In the tropical north around Cairns and Darwin the ocean is warm year‑round, typically about 24–31 °C (75–88 °F), with the wet season (summer) pushing the highest values. The eastern seaboard from northern Queensland down through New South Wales sees summer temperatures around 22–28 °C (72–82 °F) and winter values nearer 18–22 °C (64–72 °F). Southern coasts in Victoria and South Australia are cooler, with summer seas commonly 18–22 °C (64–72 °F) and winter falling to about 12–16 °C (54–61 °F). Western Australia varies from warm tropical waters in the far north to milder conditions near Perth, where summer waters are often 20–25 °C (68–77 °F) and winter 16–20 °C (61–68 °F). Tasmania and the Southern Ocean remain the coolest, with summer sea temperatures around 12–18 °C (54–64 °F) and winter sometimes as low as 8–12 °C (46–54 °F).

Swimming Conditions

Swimming around Australia is widely practiced and generally permitted, but local conditions and seasonal hazards determine where and how it is done. Popular beaches are often patrolled and have flagged swimming areas to reduce risks from rip currents, submerged hazards and marine life. In tropical northern regions there is a defined stinger season when jellyfish such as box jellyfish are more common, so nets, stinger suits or closed beaches may be used. Shark sightings are monitored and occasional closures occur, but incidents are rare relative to the number of visitors. Cooler southern waters may require wetsuits for comfort and safety. Observing local signage, swimming between the flags and heeding lifeguards keeps swimming both safe and accessible across Australia’s diverse coastline.