Gas Bay - surf spot statistics

Best Surf Season (March - May)

As autumn settles over the southwest coast, Gas Bay hits its stride. The Indian Ocean continues to churn out consistent, long-period groundswells from the SW quadrant, with average heights settling in the 1.9 to 2.3-metre range and periods stretching to 12.5–12.9 seconds. More importantly, the synoptic pattern shifts: a semi-permanent high-pressure ridge builds over the Great Australian Bight, funnelling a steady stream of offshore winds from the E to NE quadrant. With ideal wind frequencies climbing to 20–29%, you get clean, groomed faces peeling down the bay. This is the window for fun, rippable waves with the occasional pumping swell when a strong low spins up south of the continent.

Fair Surf Season (June - November)

Winter and spring deliver the biggest and most powerful swells of the year at Gas Bay. From June through August, average heights surge to 2.6–2.8 metres with periods of 13.0–13.3 seconds – true XL potential. Swell directions remain dominated by SW and WSW, wrapping beautifully into the bay. However, the wind regime becomes a double-edged sword. Frontal systems sweep across the Southern Ocean, bringing frequent onshore flows from the W and SW that can chop up the surface. Ideal offshore winds from the NE quadrant drop to 18–22% in winter and 15–18% in spring. You’ll need to pick your windows carefully, often early mornings before the sea breeze kicks in or during brief high-pressure interludes. When it lines up, expect very powerful, long period waves that demand respect.

Low Surf Season (December - February)

Summer is the quietest time at Gas Bay. Average swell heights dip to 1.8–1.9 metres, and periods shorten slightly to 11.8–11.9 seconds. While the swell direction is still predominantly SSW–SW – a favourable angle – the dominant wind pattern is the nemesis. A persistent surface trough and thermal gradients generate strong SE to SSE winds, which blow directly onshore or cross-onshore for this west-southwest-facing beach. Ideal offshore wind percentages bottom out at just 12–16%. The result is often choppy, messy conditions, though occasional fun-sized waves can be found if a southerly buster clears the air or a rare E wind sets in. For the dedicated surfer, it’s a time for grovel boards and low expectations.

August: Winter Holdover

August remains deep in winter mode. Average swell height is 2.7m with a 13.3s period – the longest average period of the year. Swell direction is still heavily weighted toward SW (25.6%) and WSW (14.0%), with a notable 8.8% in the 2–2.5m range from SW alone. However, wind patterns become even more challenging. Onshore W and WSW winds account for 22.6%, and ideal offshore winds drop to just 18%. The sea breeze cycle is strong, often ruining afternoons. The best strategy is to target early mornings or days when a strong, slow-moving high parks over the Bight, generating a persistent NNE to E flow. These windows can produce very powerful, long period waves with groomed faces.