How It Works

surf.institute aggregates data from federal ocean observation networks and presents it in a unified interface. Instead of checking multiple government websites, you can save locations and see all relevant conditions in one place.

A Location is a geographic point (like a beach, harbor, or surf break) linked to nearby data sources. Each location pulls data from the most relevant buoys, tide stations, and forecast zones. You can use our library of pre-configured locations or create custom ones with your own station assignments.

Data Sources

All data comes from U.S. federal agencies, primarily NOAA (National Oceanic and Atmospheric Administration). Data is refreshed continuously throughout the day.

NDBC

National Data Buoy Center

Moored buoys and coastal stations measuring wave height, period, direction, wind, air/water temperature, and barometric pressure. Most buoys report every 10-30 minutes.

Waves, Wind, Temperature, Pressure
CO-OPS

Center for Operational Oceanographic Products and Services

Tide gauges at harbors and coastal stations measuring water level, plus wind and meteorological data at many locations. Also provides tide predictions.

Tide Level, Predictions, Coastal Wind
CDIP

Coastal Data Information Program

High-precision directional wave buoys operated by Scripps Institution of Oceanography. Provides spectral wave data that breaks down swell into component wave trains by period and direction.

Spectral Waves, Swell Breakdown, Direction
NWS

National Weather Service

Marine forecasts for coastal waters, surf zones, and offshore areas. Includes wind forecasts, sea state, and hazard warnings. Updated twice daily.

Marine Forecast, Surf Forecast, Warnings

Key Metrics Explained

Metric What It Means Source
Wave Height Significant wave height (Hs) - average of the highest 1/3 of waves. Actual wave faces may be 1.5-2x this value. NDBC, CDIP
Wave Period Time between wave crests in seconds. Longer periods (14s+) indicate powerful ground swell; shorter periods (6-10s) indicate local wind swell. NDBC, CDIP
Wave Direction Where waves are coming FROM, in degrees (0°=North, 90°=East, 180°=South, 270°=West). NDBC, CDIP
Wind Speed Sustained wind speed, typically averaged over 2-10 minutes. Gusts may be 20-40% higher. CO-OPS, NDBC
Tide Level Water height relative to MLLW (Mean Lower Low Water). Negative values are below average low tide. CO-OPS
Water Temperature Sea surface temperature, typically measured at 1 meter depth. NDBC, CDIP
Barometric Pressure Atmospheric pressure in millibars. Falling pressure often indicates incoming weather; rising pressure indicates clearing. NDBC
Understanding Spectral Data

CDIP buoys measure the full wave spectrum, not just the dominant swell. This lets you see multiple swells arriving simultaneously - for example, a 16-second south swell mixed with 8-second northwest wind waves. The "swell breakdown" shows energy distribution across 9 period bands.

What to Watch By Activity

🏄
Surfing
Wave quality & conditions
  • Wave Height Size of incoming swell
  • Wave Period Longer = more power. 12s+ is quality ground swell
  • Direction Must align with your break's swell window
  • Wind Offshore or light winds are ideal
  • Tide Many breaks work best at specific tides
Boating & Sailing
Safety & passage planning
  • Wind Speed Primary factor for sailing; safety for all
  • Wind Gusts Plan for the gusts, not just sustained
  • Wave Height Combined seas affect comfort & safety
  • Forecast Check NWS marine forecast for trends
  • Pressure Falling pressure = weather incoming
🎣
Fishing
Conditions & access
  • Tide Many species feed on tide changes
  • Water Temp Fish activity varies with temperature
  • Wind Affects casting, drift, and boat control
  • Wave Height Bar conditions for offshore access
  • Pressure Some anglers track pressure trends
🤿
Diving & Freediving
Visibility & safety
  • Wave Height Lower is better for visibility & entry
  • Wave Period Long period = less surge underwater
  • Wind Affects surface conditions & viz
  • Water Temp Wetsuit planning
  • Tide Current strength varies with tide
🚣
Kayaking & SUP
Paddle conditions
  • Wind Primary concern - affects effort & safety
  • Wind Direction Headwinds vs tailwinds for route
  • Wave Height Surf zone & open water safety
  • Tide Current direction in channels
  • Forecast Afternoon winds often pick up
🏖️
Beach & Coastal
General conditions
  • Tide Beach access, tide pools, walking
  • Wave Height Swimming safety, beach width
  • Water Temp Swimming comfort
  • Wind Comfort for beach activities
  • Surf Forecast Rip current risk warnings

Terminology

Location
A saved geographic point linked to nearby observation stations and forecast zones. Think of it as a "conditions dashboard" for a specific place.
Station NDBC CO-OPS CDIP
A physical sensor or group of sensors at a fixed location. Buoys float offshore; tide gauges are mounted at piers and harbors.
Forecast Zone NWS
A geographic area covered by a single NWS marine forecast. Zones have codes like PZZ650 (coastal) or CAZ006 (surf zone).
Significant Wave Height (Hs)
The standard measure of wave size - the average height of the highest third of waves. Individual waves can be up to twice this height.
Dominant Period
The wave period with the most energy. Tells you whether the swell is powerful ground swell (14s+) or local wind chop (6-10s).
Spectral Data
Wave measurements broken down by frequency and direction. Shows all the different swells present, not just the dominant one.
MLLW (Mean Lower Low Water)
The reference point for tide measurements - the average of the lower low tide each day. Tide levels are shown as feet above or below MLLW.
Ground Swell vs Wind Swell
Ground swell travels long distances from distant storms (long period, organized). Wind swell is generated locally (short period, choppy).

Tips for Getting Started

1. Save a few locations. Start with places you visit regularly. Use "Clone from Library" if we have a nearby pre-configured location, or create a custom one with your own coordinates.

2. Check the station assignments. Each location pulls from specific stations. If data seems off, you might need to assign closer stations - use the "Auto-assign nearest" buttons in the location editor.

3. Learn your local patterns. Wind often picks up in the afternoon. Tides follow a ~6-hour cycle. Swell takes 1-3 days to arrive from distant storms. Over time you'll learn what readings mean for your specific spots.

4. Use spectral data for surf. If available, CDIP spectral data shows you exactly what swells are in the water - invaluable for understanding wave quality beyond just "height."

5. Read the forecast. Current observations tell you now; the NWS marine forecast tells you what's coming. Check both before heading out.

Data Freshness

Observations are pulled from source agencies continuously:

If data appears stale, the station may be offline or experiencing transmission issues - this is common with offshore buoys.