▸ FAQ — How does the Oceanic Buoy Live Feed work?
What is NOAA NDBC and where does the data come from?
The National Data Buoy Center (NDBC) is part of NOAA (National Oceanic and Atmospheric Administration). It operates a network of over 1,000 moored buoys, coastal stations and ships worldwide, continuously measuring ocean and atmospheric conditions.
This dashboard fetches the latest_obs.txt file — a single bulk download containing the most recent observation from every active station — and displays it on an interactive world map. Data typically updates every hour.
What does wave height (WVHT) mean?
Significant wave height (WVHT) is the average height of the highest one-third of waves during the measurement period. It closely matches what an experienced observer would call the "wave height" from a ship or shore.
This is different from the maximum wave height — individual waves can be 1.5–2× the significant height. Surfers typically add ~20% to WVHT to estimate face height on well-groomed groundswell.
What is dominant wave period (DPD) and why does it matter for surfing?
Dominant wave period is the period (seconds between wave crests) of the most energetic waves. Period is arguably more important than height for surf quality:
>14 seconds = groundswell — long-traveled open ocean energy. Waves are powerful, organised, and hollow. Breaks hard on reefs and sand bars.
8–14 seconds = mixed swell — a blend of local and distant energy. Decent surf, some chop.
<8 seconds = windswell — locally generated by nearby wind. Choppy, crumbly, less power. Hard to surf well.
How is the Surf Score calculated?
The Surf Score (0–10) combines several NDBC readings into a single quality metric:
Base score from wave height (WVHT): 0m=0, 6m+=10, linearly scaled.
Period bonus: DPD >14s = +1.5 points, 8–14s = +0.5 points (groundswell is better).
Wind penalty: WSPD >10 m/s = −2.0 (very strong wind destroys surface), 5–10 m/s = −1.0, <5 m/s = 0 (light/no wind = clean conditions).
Score is clamped to 0–10. A score of 7+ with DPD >14s indicates excellent conditions near a suitable break.
How does the wetsuit temperature guide work?
Water temperature (WTMP) from the buoy is used to recommend a wetsuit thickness. Keep in mind that buoys measure surface temperature at ~0.5m depth — near a shore break with upwelling it may be colder.
>24°C: Boardshorts / swimsuit
20–24°C: 2mm shorty or spring suit
17–20°C: 2/2mm full suit
14–17°C: 3/2mm full suit
11–14°C: 4/3mm full suit
7–11°C: 5/4mm full suit + boots
<7°C: 6/5/4mm + boots + gloves + hood
Why does some data show "—"?
NDBC uses MM (Missing/Measurement) as a placeholder when a sensor reading is unavailable. This happens when instruments malfunction, buoys are being serviced, or the parameter isn't measured at that station (e.g. coastal tide gauges don't measure wave height).
The dashboard converts MM to "—" for readability. Buoys without valid wave height data still appear on the map as small grey dots.
How often does the data refresh?
NOAA NDBC updates latest_obs.txt approximately every hour. This dashboard auto-refreshes every 30 minutes to stay current. The "last updated" timestamp in the hero shows when the latest fetch completed.
Individual buoy observations are timestamped in the detail card — observations older than 3 hours may indicate a delayed or malfunctioning station.
Can I find a specific buoy?
Yes — use the sort and region filters to narrow down the leaderboard list. The detail card for each buoy includes its NDBC station ID and a direct link to the full NDBC station page where you can see historical data, time series charts and station metadata.
NDBC station IDs use formats like 41001 (Atlantic), 46xxx (Pacific US), TPLM2 (Chesapeake), etc.