Niijima Seasonal Surf Averages
Swell Consistency and Wind Overview
This graph shows the percentage of days that had a ridable wind swell (7 seconds period or more) or groundswell (10 seconds period or more) of over 3ft. It also shows the dominant wind direction. Not all of these days will neccessarily give great surf, and very short lived wind swells or longer period secondary swells may produce surf not recorded, but it gives a clear idea of the seasonal trend and a rough guide to the chances of scoring something ridable.
Understanding this DataThese swell averages are calculated ONLY on swells of more than 7 seconds period. This means this is the average height of a swell that's likely to produce ridable surf NOT an average of every wave heading toward the beach in a month. Likewise the period is the average period OVER 7 seconds. There will be days that have short period wind swells that won't produce and ridable swell and these are excluded from the averages. The consistency figure gives the percentage of days that meet this condition. For example if the consistency is 50% you could expect the 'average' swell for about 15 days in the month. Of course an average tells only part of the story. A combination of very large and very small swells may produce the same average as a consistent medium sized swell.
Kamogawa (Big Ben)