Wave period, often represented by Peak Period (Tp), is the time in seconds between successive wave crests at the dominant swell frequency. It is one of the strongest indicators of surf quality.
Why period matters
Longer-period swells carry more energy and travel from distant storms, arriving as organised, powerful lines. Short-period wind swell is choppier and less powerful.
- Under 8 seconds: local wind swell, typically weak and disorganised.
- 8–12 seconds: moderate groundswell, decent surf.
- 12+ seconds: long-range groundswell, powerful and clean.