What Swell Is Considered Rough?
What Swell Is Considered Rough? Description Height (metres) WMO Sea State code Smooth 0.1 – 0.5 2 Slight 0.5 – 1.25 3 Moderate 1.25 – 2.5 4 Rough2.5 – 4 5 What is considered a big swell? Ground swell” refers to a swell that has a wave period of roughly 12 seconds or higher. Wind