Wave charts

A quick guide to wave charts

Wave charts describe waves across the oceans. Sounds simple, eh ?
But if you look at the sea surface in open ocean you see an almost random pattern. With hundreds of waves, each with different heights and directions.

Wave charts cannot show every wave and every ripple. They usually show only one type of wave at a given position. The three main types of wave are Swell (long-travelled waves), Windsea (short-travelled waves) or Significant waves (a mathematical average of swell and windsea).

To simplify things further, wave charts usually only display one or two of the following three characteristics that are needed to fully describe a wave -

Wave height
Wave direction
Wave period

The first two are fairly obvious. Wave period is the time (in seconds) between successive waves. Ideal surfing conditions are when long period swells (more than about 12 seconds between waves) hit the coastline at a time when there are light winds locally (and therefore small windsea).

Wave height & direction charts

In order to track the long-travelled waves that lead to "classic" surfing conditions, you need to study Swell charts. Unfortunately, nearly all of the wave charts available on the internet are for Significant waves, which tend to only be a good indicator for beach waves when there is not long-travelled swell.

On Significant wave charts, waves that have been marching along for days (swell waves), may suddenly all but disappear. Remember - The long swell waves are still there, but the chart has masked them with locally-generated (windsea) waves.

Meteosim European significant wave height & direction
The latest North Atlantic significant wave height & peak direction
From NOAA/NCEP

The latest North Atlantic significant wave height & mean direction
From NOAA/NCEP

The latest North Atlantic significant wave height & direction, from Oceanweather

The latest Mid Atlantic significant wave height & direction, from Oceanweather

Todays global significant wave height & direction, from NOAA

	Red indicates greater than 5 metre significant wave height
	Peach indicates greater than 2.5 metre significant wave height
	Other colours indicate no data due to fog, ice or equipment failure

Wave period charts

Wave period is the time (in seconds) between successive waves. Wave period charts show either Swell period (long-travelled waves), Windsea (short-travelled waves), or Peak period (a mathematical average of swell and windsea wave periods).

In order to track the long-travelled waves that lead to "classic" surfing conditions, you need to study Swell charts (for both wave height and wave period). Unfortunately, nearly all of the wave period charts available on the internet are for Peak period, which tend to only be a good indicator for beach waves when there is not long-travelled swell.

On Peak period charts, waves that have been marching along for days (swell waves), may suddenly all but disappear. Remember - The long swell waves are still there, but the chart has masked them with locally-generated (windsea) waves.

European wave period, midday today, from Meteosim

The latest North Atlantic peak wave period & direction, from NOAA

The latest North Atlantic peak wave period and peak direction
From NOAA/NCEP