Inamuragasaki - surf spot statistics

Best Surf Season (October - March)

The winter months deliver the most consistent and quality surf to Inamuragasaki. As the Siberian high strengthens, a steady stream of cold fronts and low-pressure systems track across the East China Sea, firing long-period groundswells from the SW through S quadrants directly into this south-facing beach. The dominant NNE and N winds blow offshore, grooming the waves into clean, punchy lines. While average wave heights hover around 0.7–0.8 m, the combination of favorable swell direction and frequent offshore flow creates fun, rippable conditions. October and March offer the highest percentage of ideal wind, while December through February see the peak in SW swell energy.

Fair Surf Season (April - June)

Spring marks a transition period as the winter storm track weakens and the Pacific High begins to build. Swell direction shifts to more SSE and S, which still hit the spot well, but average wave heights remain modest at 0.7–0.8 m with periods settling around 7.8–8.0 s. The wind regime becomes less predictable – NNE offshore breezes still occur, but onshore SSW and SW winds increase, especially by late spring. Ideal wind percentages drop to 16%. Expect plenty of rideable days, but with more chop and fewer long-period gems.

Low Surf Season (July - September)

Summer brings the lowest surf consistency to Inamuragasaki. The dominant swell shifts to S and SSE, which are still acceptable directions, but average wave heights remain under 0.8 m. The real issue is the wind: the summer monsoon pumps onshore SSW and SW winds over 40% of the time, while the percentage of ideal offshore wind plummets to just 14–18%. Though August and September see a slight uptick in average wave period (up to 9.3 s) from distant typhoon swells, these events are often accompanied by strong, unruly wind. When a typhoon tracks just right and the wind clocks offshore, the spot can suddenly come alive with powerful, long-period surf – but those windows are rare and fleeting.

January: The Peak of Winter Swell

January is the heart of the winter swell season for Inamuragasaki. Swell energy is dominated by the SW direction, which accounts for 29% of total wave activity, with a significant chunk in the 0.5–1.5 m range. Periods average 7.8 s, putting most waves in the average, punchy, rideable category. The wind is favorable 16% of the time, with NNE offshore flows making up the lion’s share at 29% of all wind observations. However, onshore SW and WSW winds occur around 17% of the time, often spoiling the surface. When a cold front clears out the sky and NNE winds set in, the SW groundswell lines up cleanly – that’s when Inamuragasaki really fires.