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L4 wave buoy monthly means for 2026

Monthly means from the L4 wave buoy for 2026, including available wave height, period, direction, wind and sea temperature data.

Last observation shown

Data available:  to 

Latest

Typical Significant Wave Height

1.5ft
Mean: 1.6 ft
P10–P90: 0.8 — 2.9 ft
Recorded extremes

0 — 4.9 ft

Mean Observed Wave Period

5.2secs
P10–P90: 3.7 — 7.1secs
Recorded extremes

2.6 — 10.5secs

Available for 509 of 524 hourly samples

Typical Observed Wind

-, -mph
Mean: - mph
P10–P90: - — - mph

Available for 0 of 524 hourly samples

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 524 hourly samples

Chart showing grouped wave observations for L4. Use the table on this page for a text version of the same measurements. To open daily observations, use a linked month name in the table.

About L4 wave buoy

L4 (WMO 62030) is the Western Channel Observatory's coastal site about six nautical miles south of Plymouth. Weekly sampling at L4 resumed in 1988 and its autonomous buoy has supplemented that ship-based time series since 2008, making the site an unusually rich long-term record of the western English Channel.

Its current data sources report wave height, wave period, wave direction, directional spread, wind conditions, sea temperature, separate swell and wind-sea components and wave spectra.

Metrics are rows; months run left to right.
L4 wave buoy monthly means 2026Last observation shown
Metric
Mean significant wave height (ft)------12----
Mean average wave height (ft)------11----
Mean maximum wave height (ft)------12----
Mean maximum crest height (ft)------------
Mean maximum trough height (ft)------------
Mean peak period (s)------45----
Mean average period (s)------44----
Mean period Tm02 (s)------------
Mean zero-crossing period (s)------------
Mean maximum wave period (s)------------
Mean peak wave direction------ENEconcentration 89%Variableconcentration 22%----
Mean wave direction------------
Mean directional spread (°)------------
Mean wind direction------------
Mean wind speed (mph)------------
Mean water temperature(°C)------------

Swipe sideways to see more months.

Wave metric colour key

Colours move through the scale as each number increases. They do not by themselves mean that conditions are good, safe or suitable for you.

Wave & swell height0–40+ ft
Wave & swell period0–22+ s
Wind speed0–75 mph

The displayed numbers remain the source of truth; colour is an additional visual cue.

What does buoy wave power mean?

kW/m means kilowatts of wave power per metre of wave crest. It describes the rate at which the observed sea state carries energy past the buoy.

Unlike the shore-directed forecast value, buoy wave power is the total power at the observation point. It is not projected towards a particular beach and does not predict breaking wave height.

In deep water, wave power can be calculated with:

P is approximately 0.49 times significant wave height squared times wave energy period.

P is power in kW/m, Hs is significant wave height in metres, and Te is wave energy period in seconds.

  • Provider-reported power is used when available.
  • Otherwise, a value is calculated only when both significant height and a genuine energy period are available. The ≈ symbol marks calculated values.
  • A dash is shown instead of substituting peak, Tm02, zero-crossing or other period measurements.
  • Daily and monthly figures use the mean of hourly-normalized observation power values; they are not calculated from mean height and period.

Wave direction, spectrum, water depth and local bathymetry still matter. Wave power is best read alongside height, period and direction rather than as a standalone surf-quality score.

The observation data displayed on this page is from the Met Office Marine observations.
The observation data displayed on this page is from the Western Channel Observatory.

Learn how SurfHog combines, checks and summarizes observations in the data and methodology notes.

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