Monobegawakakou seasonal overview
Best Surf Season (September - November)
The Pacific around Shikoku is at its restless best from late summer into autumn. This is when the tropical cyclone machine of the northwest Pacific spins up, and Monobegawakakou's south-facing stretch starts receiving consistent, longer-period swell out of the SE, SSE and S. September and October are the crown jewels: average periods climb to 9.3-9.5s, ideal offshore wind windows hit 46-56%, and water temps remain in the low-to-mid 20s (72-77°F / 22-25°C). As the Siberian High begins to strengthen, N, NNW and NNE winds groom the lines between passing systems. November carries the same storm track but with slightly less energy and smaller average heights, though the combination of clean offshore wind and lingering warm water can still produce excellent sessions.
Fair Surf Season (December - April)
Winter and early spring are driven by the Siberian High and a strong Aleutian Low track. The beach is frequently glassed by offshore NW-NNW winds, but the average swell size drops to around 2-3ft (0.6-0.9m) with periods peaking only in the 8-9s range. Storms in the East China Sea and western Pacific can send punchy S and SSE swells into the coastline, and the exposed south aspect keeps the wave facing properly. March and April are the pick of this block: longer days, ocean water still cool but not freezing, and the SE/SSE swell window begins to fill in more consistently with 44% ideal wind days.
Low Surf Season (May - July)
The summer monsoon and the Baiu/Meiyu rainy front settle over southern Japan, bringing light, often onshore southerly winds and a dominant short-period windswell. Average wave heights hover around 3ft (1m) but the periods fall to 7.4-8.1s, meaning the beach often sees soft, crumbly and sectiony surf rather than powerful lines. The rare exception comes when a tropical depression or early-season typhoon tracks far enough south to send a clean SSW-SE pulse, but the wind direction is usually against you at the beach. This is the season for a grovel board and patience, not for epic Shikoku walls.