How to Read a NOAA Buoy Report
A NOAA buoy report is a set of instrument readings — wave height, wave period, wind, temperature and pressure — taken at a fixed point offshore and published hourly. Reading one means knowing which numbers describe the swell and which describe the weather on top of it.
A buoy is the only honest number in surf forecasting. A model predicts; a buoy measures. When you open a station page on PierMonkey you are looking at what an instrument in the water recorded in the last hour, not what a computer expects to happen.
The trade-off is that buoys report in a terse, abbreviated format designed for mariners, not surfers. Here is what each field means and, more usefully, which ones matter.
Every field on the report
| Code | Name | What it means |
|---|---|---|
| WVHT | Significant wave height | The average height, trough to crest, of the highest one-third of waves in the sampling window. Not the biggest wave, and not the average wave. Roughly what an experienced observer would call "the wave height" by eye. |
| DPD | Dominant wave period | The period of the swell carrying the most energy, in seconds. The single most predictive number on the report — see swell period below. |
| APD | Average wave period | The mean period across all wave energy present. When APD sits far below DPD, there is short-period chop riding on top of a longer groundswell. |
| MWD | Mean wave direction | The compass bearing the dominant swell is coming FROM, in degrees. 270 means a swell out of the west. |
| WSPD / GST | Wind speed and gust | Wind at the buoy. Offshore-buoy wind is not beach wind — it tells you what is generating or degrading swell out at sea, not whether your break is glassy. |
| WDIR | Wind direction | Again, the direction the wind is coming FROM. |
| WTMP | Water temperature | Sea-surface temperature at the buoy. Wetsuit maths. |
| PRES | Barometric pressure | Air pressure. A falling barometer offshore means a system is deepening — often the swell that arrives two days later. |
Which fields actually predict surf
Height and period, in that order of familiarity but the reverse order of importance. A report of 2 ft at 18 seconds will produce dramatically more rideable surf than 4 ft at 6 seconds, because period governs how much energy sits beneath the surface and how the wave behaves when it reaches shallow water.
Direction is the third number, and it is a gate rather than a dial: swell arriving from outside a break's window is largely blocked by whatever headland, island or continental shelf sits in the way, no matter how big it is offshore.
What a buoy cannot tell you
A buoy reports the sea state at the buoy. It is not at your break. Offshore buoys sit in deep water tens or hundreds of nautical miles out, and the swell they measure still has to travel, refract around bathymetry, and shoal before anyone rides it.
It also cannot tell you about local wind at the beach, sandbar condition, tide stage, or crowd. Those decide whether a good swell becomes a good session.
Reading one on PierMonkey
Each station page shows the current readings, recent history, and — where the station supports it — a spectral breakdown separating overlapping swell trains, plus a 16-day forecast for the same location. Stations near a covered break link straight through to that break's guide.
See it on live data
The fastest way to make any of this concrete is to go and look at the numbers being described.
Common questions
How often do NOAA buoys update?▾
Why does the buoy show no wave height?▾
Which buoy should I watch for my break?▾
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