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Île de Batz wave buoy daily means for Aug 2025

Daily means from the Île de Batz wave buoy for Aug 2025, including available wave height, period, direction, wind and sea temperature data.

Last observation shown

Data available:  to 

Monthly means for

Latest

Period Summary

Programmatically generated summary. Hog Says

1,488 wave-buoy observations covered all 31 days. Typical wave height was 2.6 ft (10th–90th percentile 1.6–6.9 ft), while mean peak wave period was 9.1 seconds (10th–90th percentile 5.5–12.5 seconds). Typical calculated wave power was approximately 2 kW/m (10th–90th percentile 0.7–23.8 kW/m), derived from significant wave height and energy period. 1 of 4,464 checked values (0%) were excluded by quality control. Across 4 comparable years, mean wave height was above the same-month mean of 2.9 ft and mean wave period was above the same-month mean of 8.2 seconds.

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

Typical Significant Wave Height

2.6ft
Mean: 3.5 ft
P10–P90: 1.6 — 6.9 ft
Recorded extremes

0.8 — 10.5 ft

Mean Observed Wave Period

9.1secs
P10–P90: 5.5 — 12.5secs
Recorded extremes

3.7 — 21.2secs

Typical Wave Power

Approximately 1.97kW/m
Mean: 7.29kW/m
P10–P90: 0.69 — 23.82kW/m
Recorded extremes

0.22 — 55.07kW/m

Calculated from significant wave height and energy period.

Typical Observed Wind

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

Available for 0 of 744 hourly samples

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 744 hourly samples

Compared With Previous Augusts

Historical baseline from 5,947 observations across 4 years.

Wave Height
3.5ft
0.6ft above mean
Historical mean 2.887ft
Wave Period
9.1s
0.9s above mean
Historical mean 8.2s
Water Temperature
–
Not enough comparable data

Chart showing grouped wave observations for Île de Batz. Use the table on this page for a text version of the same measurements. To open hourly observations, use a linked day name in the table.

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; days run left to right.
Île de Batz wave buoy daily means Aug 2025Last observation shown
Metric
Mean significant wave height (ft)4324QC rejected53344222223322322212787769
Mean maximum wave height (ft)6536107556743333443343332310111210913
Mean peak period (s)77779109910111010987866555119811151312111012
Mean average period (s)665689889108897665555589791412119910
Mean period Tm02 (s)55456766876676554444456571098778
Mean peak wave directionWNWconcentration 98%NWconcentration 95%WNWconcentration 99%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 99%WNWconcentration 92%WNWconcentration 100%WNWconcentration 100%NWconcentration 84%NWconcentration 76%NNEconcentration 100%NNEconcentration 100%NNEconcentration 100%NNEconcentration 100%Nconcentration 99%WNWconcentration 93%WNWconcentration 100%WNWconcentration 99%WNWconcentration 99%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%WNWconcentration 100%
Mean directional spread (°)24.329.926.723.419.619.522.322.821.221.526.427.927.628.328.323.221.924.126.724.230.730.128.532.027.022.720.318.720.522.019.7
Mean water temperature(°C)-------------------------------

Swipe sideways to see more days.

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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