Macaronis Swell Window
Mentawai Islands, Indonesia · part of the Macaronis spot guide
- Swell window (from)
- 180°–280° (S–W)
- Best direction
- ~225° (SW)
- Period sweet spot
- 13–18 s
- Open-ocean height (Hs)
- 2–10 ft
- Resulting faces
- 2–8 ft
Open-ocean vs. the face: the heights on buoys and forecast models are significant wave height (Hs) in deep water. What you ride is the breaking face, which depends on period, direction and this break's bathymetry — that's why the two rows above differ. PierMonkey's spot ratings already do this conversion for you.
The window runs from south through southwest to west, matching the bay geometry, with the optimum at southwest where a groundswell lines the reef up most mechanically all the way down. Only south-through-west energy wraps into the bay — anything more westerly or southerly refracts before it arrives, which is exactly what shaves size and cleans up the wall. It wants long period, roughly 13-to-18 seconds.
Because the bay attenuates the swell, the breaking face runs similar to or slightly below the open-ocean height — not amplified like an exposed reef. Read the alert threshold as open-ocean height.