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Île de Batz wave buoy observations on Thu, Sep 18, 2025

Hourly readings from the Île de Batz wave buoy for Thu, Sep 18, 2025, including available wave height, period, direction, wind and sea temperature data.

Last observation shown

Oldest observation available

Daily means for

Latest

Period Summary

Programmatically generated summary. Hog Says

48 wave-buoy observations were recorded during the day. Typical wave height was 5 ft (10th–90th percentile 4.3–6.2 ft), while mean peak wave period was 10.5 seconds (10th–90th percentile 9.9–11 seconds). Typical calculated wave power was approximately 10.7 kW/m (10th–90th percentile 7.5–16.2 kW/m), derived from significant wave height and energy period. All 144 checked values passed quality control.

Generated only from the observations and comparisons shown on this page.

Line chart showing wave height, wave period and sea temperature for Île de Batz. Use the detailed observations table below for the same data in text form.

About Île de Batz wave buoy

Île de Batz is a CANDHIS directional buoy off northern Brittany, within the French national sea-state observatory coordinated by Cerema. The station sits at the western entrance to the English Channel, where Atlantic swell rounds Brittany towards the exposed Finistère and Channel coasts.

Its current data source reports wave height, wave period, wave direction, directional spread and sea temperature.

Metrics are rows; hours run left to right. Times use your device time zone.
Île de Batz wave buoy hourly observations Thu, Sep 18, 2025Last observation shown
Metric
Significant wave height (ft)777666666656565545555555556555565555555554444444
Maximum wave height (ft)101512991210989999108761077897671098798108888878778866677
Peak period (s)111111111111119109101091010101012101010101010101111111111111011111111121211111111111111111110
Average period (s)10101010101099999999910991099999991099991010101010101010101010101091099
Mean period Tm02 (s)888778777777777777888877778777787877888888888888
Peak wave directionWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNWWNW
Directional spread (°)23.821.520.222.125.022.725.121.021.821.923.522.523.118.523.517.625.022.320.825.321.023.024.726.225.119.218.627.226.023.722.822.622.322.625.421.818.522.518.822.720.920.122.125.129.626.024.524.1
Water temperature(°C)------------------------------------------------

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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 Cerema CANDHIS coastal wave observatory.

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

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