Kugenuma - surf spot statistics

Best Surf Season (September - November, March)

As the North Pacific transitions into autumn, the Jet Stream strengthens and low-pressure systems become more frequent, driving consistent, quality swell toward the coast of Japan. September through November sees the highest percentage of ideal light offshore winds at Kugenuma, peaking in October at 20%. During these months, the average wave period climbs to 8-9 seconds, indicating punchy, rideable waves. The dominant swell directions from the S, SSW, and SW align perfectly with the beach's SSW exposure, delivering fun to solid sized waves in the 1-1.5m range. Equally important, the NNE and N wind regimes dominate, grooming the surf cleanly. March is another prime month as the spring transition kicks in, with 18% ideal winds and a similar swell pattern, making it a reliable shoulder season.

Fair Surf Season (December - February, April - May)

The winter months of December through February bring the largest and most powerful swell of the year, especially from the SW, with waves often exceeding 1.5m. However, the trade-off is a higher frequency of strong onshore winds (SW, SSW) that can chop up the surface. The ideal wind percentage drops to 14-17%, but when a cold front passes and high pressure builds from the north, the conditions can turn on quickly with clean, long-period swell. In April and May, the swell activity decreases and the wave heights become more modest, averaging 0.7-0.8m. The wind patterns are shifting—NNE winds still provide offshore flow, but the increasing influence of afternoon sea breezes from the S and SSW degrades conditions. Still, morning sessions can deliver small, fun waves, especially on a southerly swell.

Low Surf Season (June - August)

Summer is the quietest time for consistent surf at Kugenuma. The Pacific high-pressure system dominates, leading to lighter, but often onshore winds. The ideal wind frequency drops to 14-16%. Swell is predominantly from the SSE and S with short, weak periods under 8 seconds, resulting in small, choppy conditions most days. However, this is also typhoon season, and the occasional tropical storm or typhoon tracking north of Japan can send a burst of long-period SE to S swell that lights up the point. These events are sporadic, but when they align with a brief window of offshore wind (N to NE), Kugenuma can offer surprisingly fun, rippable waves. For the most part, though, expect micro-sessions and groveling conditions throughout the summer months.

January: The Depth of Winter Swell

January delivers the largest average swell of the year, with the SW direction dominating at 29.2% of all observations. This is the core of the winter storm track, where extratropical cyclones in the Sea of Japan send powerful, long-period swell into Sagami Bay. Average wave heights hover around 0.7m, but a significant portion (nearly 20%) reaches 1-1.5m or larger, offering solid, rippable waves. The average period of 7.8 seconds means the swell is mostly in the average, punchy range. Wind-wise, the spot benefits from a strong NNE flow (29.3%) and N winds (12.5%), which blow directly offshore and groom the faces clean. However, when the wind swings to SW (7.1%) it's game over—choppy and blown out. Ideal surfing conditions occur only 14% of the time, but when the stars align, the combo of offshore wind and southwest groundswell makes for classic Kugenuma barrels.