Surf forecastStatisticsHistorical report

Rottnest Island seasonal overview

Best Surf Season (May - September)

Winter unleashes the full power of the Southern Ocean on Rottnest Island. The subtropical ridge shifts north, allowing a parade of strong extratropical storms to generate consistent, long-period SW and SSW swell. Average wave heights climb to 2.5-2.7m with periods often exceeding 12s, pushing into the powerful, long-period range. Critically, the frequency of offshore north-quadrant winds (N, NNW, NW) peaks during this period, as cold fronts approach from the west. These conditions create clean, hollow waves at south-facing breaks, with ideal wind percentages reaching 15-16%. The combination of size, period, and favorable wind makes this the premium window for serious surf.

Fair Surf Season (April & October)

These transitional months offer a blend of winter swell and lighter, more variable winds. April sees average heights of 2.0m and a good 11% offshore wind occurrence, as the first winter storms begin to fire up. Swell directions shift more toward the SSW/SW, and periods lengthen to 12-13s, delivering punchy, rideable waves. October offers similar size (2.2m) but the wind is more fickle, with only 7% ideal offshore flow. However, the back half of frontal passages can still produce short-lived windows of clean, lined-up swell. Both months reward flexible surfers who can pick the right day.

Low Surf Season (November - March)

During the austral summer and early autumn, Rottnest is largely dominated by unfavorable onshore winds from the south and southwest. The subtropical ridge strengthens, bringing persistent SE to SW airflow—directions that blow directly across the spot and ruin wave quality. With ideal offshore wind percentages ranging from 3-6%, clean sessions become a rarity. Swell heights drop to 1.8-1.9m on average, though long-period energy from distant Southern Ocean storms can still sneak in. When a brief northerly land breeze or a passing tropical disturbance aligns with a decent SSW swell, the magic can happen—but these moments are fleeting. Patience is key during these months.

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Conditions at Rottnest Island in May

May: Into the Groove

May marks the start of the main winter season. Average swell height reaches 2.2m with a 12.7s period, and the ideal wind percentage ticks up to 15%. The wind distribution now shows significant contributions from the north quadrant: N (3.4%), NNE (4.4%), NE (7.1%), ENE (9.4%)—these are offshore or cross-offshore directions for a south-facing spot. SW swell (42.1%) remains king, but WSW (16%) and W (3.7%) also become more prominent, indicating a wider fetch. The combination of long-period groundswell and more frequent north winds creates excellent surf conditions. Waves in the 1.5-2.5m range are common, offering punchy, powerful walls that bow perfectly along the reefs.

Average Spot conditions at Rottnest Island in May

Swell history for May

0 - 0.5
0.5 - 1
1 - 1.5
1.5 - 2.0
2.0 - 2.5
> 2.5 m

Wind history for May

0 - 10
10 - 20
20 - 30
30 - 40
40 - 50
> 50 km/h

Swell quality

Analyze the groundswell consistency at Rottnest Island during May. Based on historical data, there is a % probability of groundswell occurring this month. The chart below provides a detailed breakdown of the average wave height distribution, offering deep insights into the swell quality and surf potential you can expect at Rottnest Island for your next trip in May.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Rottnest Island for May. Our analysis shows that favorable offshore or side-shore winds coincide with surfable swell approximately % of the time. The accompanying graph illustrates the average size distribution of waves during these optimal wind windows at Rottnest Island.

Swell with good wind

Swell with good wind by size