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Plateau du Four wave buoy daily means for Mar 2025

Daily means from the Plateau du Four wave buoy for Mar 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

1,486 wave-buoy observations covered all 31 days. Typical wave height was 2.9 ft (10th–90th percentile 1.8–5.4 ft), while mean peak wave period was 9.7 seconds (10th–90th percentile 4–13.6 seconds). Typical calculated wave power was approximately 2.8 kW/m (10th–90th percentile 1.1–9.7 kW/m), derived from significant wave height and energy period. 32 of 4,458 checked values (0.7%) were excluded by quality control. Across 15 comparable years, mean wave height was below the same-month mean of 4.7 ft and mean wave period was below the same-month mean of 10.1 seconds.

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

Typical Significant Wave Height

2.9ft
Mean: 3.3 ft
P10–P90: 1.8 — 5.4 ft
Recorded extremes

1.3 — 9.6 ft

Mean Observed Wave Period

9.7secs
P10–P90: 4 — 13.6secs
Recorded extremes

2.7 — 18.8secs

Available for 739 of 743 hourly samples

Typical Wave Power

Approximately 2.83kW/m
Mean: 4.57kW/m
P10–P90: 1.09 — 9.73kW/m
Recorded extremes

0.41 — 38.08kW/m

Calculated from significant wave height and energy period.

Typical Observed Wind

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

Available for 0 of 743 hourly samples

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 743 hourly samples

Compared With Previous Marchs

Historical baseline from 21,003 observations across 15 years.

Wave Height
3.3ft
1.4ft below mean
Historical mean 4.724ft
Wave Period
9.7s
0.4s below mean
Historical mean 10.1s
Water Temperature
–
Not enough comparable data

Chart showing grouped wave observations for Plateau du Four. 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 Plateau du Four wave buoy

Plateau du Four is a CANDHIS station associated with the SEM-REV offshore test site off Loire-Atlantique. Located near a shallow offshore bank west of Le Croisic, it supplies environmental context for marine-energy research and for an exposed sector between the Loire estuary and southern Brittany.

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

Metrics are rows; days run left to right.
Plateau du Four wave buoy daily means Mar 2025Last observation shown
Metric
Mean significant wave height (ft)3322245644222232244567642223432
Mean maximum wave height (ft)45433689764334543578910864335643
Mean peak period (s)-141413137881010811141386411978101010991012111110
Mean average period (s)4798856789765944377679987787878
Mean period Tm02 (s)3555645567544643355557765555555
Mean peak wave directionNNEconcentration 71%Wconcentration 71%Wconcentration 100%Wconcentration 100%Wconcentration 100%Sconcentration 80%SSWconcentration 81%SSWconcentration 96%WSWconcentration 95%WSWconcentration 100%Wconcentration 67%WNWconcentration 64%Wconcentration 98%WSWconcentration 100%NNWconcentration 51%Nconcentration 56%ESEconcentration 89%SWconcentration 66%SWconcentration 86%Sconcentration 99%SSWconcentration 91%WSWconcentration 95%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%
Mean directional spread (°)31.332.832.131.331.829.125.123.623.222.325.730.034.823.926.728.230.026.422.222.221.219.221.725.629.926.423.826.625.428.428.2
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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