Choshi - surf spot statistics

Choshi, Japan, offers surfable waves year-round, but the best conditions are typically found during the winter months, from November to February. During this period, ground swell makes up a significant portion of the swell mix (32-48%), providing more consistent and cleaner waves compared to wind swell, which dominates the rest of the year. The mean swell size is also slightly larger in winter (1.6-1.8m), offering better surf potential. However, wind conditions are far from ideal, with only 24-28% of days having favorable winds—offshore or light cross-shore—while the majority of days see onshore or strong winds that can degrade wave quality. From March to October, wind swell becomes increasingly dominant, peaking from May to July (75-91% of swells), which often results in choppier, less organized waves. The swell size drops slightly (1.4-1.8m), and the chances of good winds remain low (16-22%). Late September and October can still see decent swells (1.8m) but suffer from inconsistent winds. Overall, if you're seeking the best balance of swell size and quality, late autumn to early winter (November-February) is the prime window, despite the frequent poor winds. Summer and spring months are less reliable, with smaller, wind-affected waves dominating. For dedicated surfers, patience and selective timing around wind forecasts are key to scoring good sessions in Choshi.

December at this surf spot offers decent conditions with an average swell height of 1.6m and a solid period of 9.7s, suggesting well-formed and rideable waves. The majority of swells come from the NE to ENE directions, providing consistent energy, with a notable portion (7.18% NE, 6.00% ENE) in the 1-1.5m range—ideal for intermediate to advanced surfers. Larger swells (1.5-2.5m) are frequent enough (6.24% NE, 3.49% ENE) to deliver powerful sessions, though they drop off sharply beyond 2.5m. Cross-shore or light onshore winds (28% clean) are manageable, but stronger W to NW winds (over 20kph in 5–15% of cases) can create chop. Expect smaller, less consistent swells from S-SSW directions, mostly under 1.5m. Overall, December is a reliable month with good size and shape, though wind conditions require monitoring for optimal sessions.