Western Australia – Water Temperature Overview

Current Sea Water Temperature

It’s important to note that these swimming tips and recommendations apply only in settled weather. When air temperatures drop below 20°C — and sometimes even below 25°C — swimming can feel uncomfortable, even when water temperatures are relatively high.

Water Temperature and Swimming Conditions by Month

Western Australia has the longest coastline in the country, and sea water temperatures vary widely from north to south. Along the tropical north, sea temperatures are warm throughout the year, generally ranging from about 25–27 °C in winter to 28–30 °C in summer. Further south, along the Indian Ocean coast, temperatures become more seasonal, typically sitting around 18–20 °C in winter and rising to 21–24 °C in summer. This wide range means swimming conditions differ greatly depending on location and time of year.

Swimming Conditions

Swimming opportunities along the WA coast reflect these temperature patterns. In the north, the sea remains warm enough for swimming in all seasons, with summer water often feeling very warm during periods of high humidity. In the central and southern coastal regions, summer and early autumn provide the most comfortable swimming conditions, when water temperatures reach their annual peak. Winter swimming is less common in the south due to cooler water, while sheltered bays and lagoons can feel noticeably warmer than open ocean beaches, especially on calm days.

Most Viewed Sea Places in the Western Australia

Current Water Temperature in Lakes and Rivers

Inland Western Australia includes rivers, gorges, and man-made lakes that respond quickly to extreme air temperatures. During summer, inland water temperatures commonly rise to between 24 and 30 °C, particularly in shallow pools and slow-flowing rivers. These warm conditions make inland swimming attractive during hot weather, when air temperatures regularly exceed those along the coast. In contrast, deeper reservoirs may stay slightly cooler but still provide comfortable swimming conditions through much of the warmer months.

Seasonal rainfall has a strong influence on inland swimming conditions. In northern parts of the state, the wet season can bring cooler, fast-flowing water and temporary changes in temperature, while the dry season allows water temperatures to stabilise. In the south, inland waters cool quickly outside summer, often dropping below 18 °C by autumn. Winter water temperatures are generally too low for casual swimming. Overall, Western Australia offers a broad spectrum of swimming conditions, from consistently warm tropical seas in the north to more seasonal coastal and inland waters further south, with summer providing the best conditions across most of the state.