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Les Pierres Noires wave buoy daily means for May 2017

Daily means from the Les Pierres Noires wave buoy for May 2017, 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

1,463 wave-buoy observations covered all 31 days. Typical wave height was 3.9 ft (10th–90th percentile 2.1–7 ft), while mean peak wave period was 9.7 seconds (10th–90th percentile 7.8–11.8 seconds). Typical calculated wave power was approximately 5.7 kW/m (10th–90th percentile 1.6–20.7 kW/m), derived from significant wave height and energy period. 7 of 4,389 checked values (0.2%) were excluded by quality control. Across 7 comparable years, mean wave height was below the same-month mean of 4.9 ft and mean wave period was above the same-month mean of 9.5 seconds.

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

Typical Significant Wave Height

3.9ft
Mean: 4.4 ft
P10–P90: 2.1 — 7 ft
Recorded extremes

1.1 — 17.3 ft

Mean Observed Wave Period

9.7secs
P10–P90: 7.8 — 11.8secs
Recorded extremes

3.1 — 16.1secs

Typical Wave Power

Approximately 5.65kW/m
Mean: 9.63kW/m
P10–P90: 1.64 — 20.74kW/m
Recorded extremes

0.53 — 138.36kW/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 Mays

Historical baseline from 10,328 observations across 7 years.

Wave Height
4.4ft
0.5ft below mean
Historical mean 4.888ft
Wave Period
9.7s
0.2s above mean
Historical mean 9.5s
Water Temperature
–
Not enough comparable data

Chart showing grouped wave observations for Les Pierres Noires. 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 Les Pierres Noires wave buoy

Les Pierres Noires is a CANDHIS directional buoy west of Brittany, maintained through the French national sea-state observatory and its scientific and maritime partners. Its position near the offshore reef and lighthouse represents fully exposed Atlantic conditions approaching the Iroise Sea and western 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.
Les Pierres Noires wave buoy daily means May 2017Last observation shown
Metric
Mean significant wave height (ft)QC rejected664433332235678776534532443333
Mean maximum wave height (ft)1899754545334791013111110756753664554
Mean peak period (s)1091113810810119987891011111099101081011111012109
Mean average period (s)9810106779768768791010977998910991198
Mean peak wave directionWNWconcentration 97%Wconcentration 98%Wconcentration 100%Wconcentration 100%SSWconcentration 43%WSWconcentration 100%SWconcentration 99%WSWconcentration 99%WSWconcentration 96%SWconcentration 61%SWconcentration 100%SWconcentration 97%SWconcentration 95%WSWconcentration 98%Wconcentration 98%WSWconcentration 100%WSWconcentration 100%Wconcentration 99%WNWconcentration 100%WNWconcentration 100%Wconcentration 99%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%Wconcentration 100%WSWconcentration 100%WSWconcentration 100%Wconcentration 99%
Mean directional spread (°)24.930.821.524.434.828.827.925.229.329.625.426.830.129.628.221.623.025.924.928.028.322.523.827.527.125.026.228.225.327.827.9
Mean 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.

Observation data source

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

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