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Brittany wave buoy daily means for Dec 2020

Daily means from the Brittany wave buoy for Dec 2020, 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

742 wave-buoy observations covered all 31 days. Typical wave height was 13.5 ft (10th–90th percentile 6.6–24.1 ft), while mean reported wave period; measurement type unavailable was 7.9 seconds (10th–90th percentile 6–10 seconds). Typical wind was 24.2 mph (10th–90th percentile 15–33.3 mph). 3 of 2,968 checked values (0.1%) were excluded by quality control. Across 10 comparable years, mean wave height was above the same-month mean of 13.7 ft and mean wave period was below the same-month mean of 8.2 seconds.

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

Typical Wave Height

13.5ft
Mean: 14.9 ft
P10–P90: 6.6 — 24.1 ft
Recorded extremes

3.6 — 35.4 ft

Available for 739 of 742 hourly samples

Mean Wave Period

7.9secs
P10–P90: 6 — 10secs
Recorded extremes

5 — 12secs

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 742 hourly samples

Typical Wind

WNW, 24.2mph
Mean: 24.3 mph
P10–P90: 15 — 33.3 mph
Recorded extremes

4.7 — 43.8 mph

Circular concentration: 58%

Compared With Previous Decembers

Historical baseline from 7,169 observations across 10 years.

Wave Height
14.9ft
1.2ft above mean
Historical mean 13.7ft
Wave Period
7.9s
0.3s below mean
Historical mean 8.2s
Water Temperature
–
Not enough comparable data
Historical mean 13.4°C

Chart showing grouped wave observations for Brittany. 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 Brittany wave buoy

Brittany buoy (WMO 62163) is maintained jointly by the UK Met Office and Météo-France in the Bay of Biscay. Its exposed position west of Brittany monitors Atlantic conditions approaching western France and the western entrance to the English Channel. The international feed can include wind, pressure, temperature and wave observations when available.

Metrics are rows; days run left to right.
Brittany wave buoy daily means Dec 2020Last observation shown
Metric
Mean wave height (ft)56182323101610810171813201516111620151311191578283121119
Mean observed period(s)6Reported6Reported9Reported10Reported10Reported7Reported8Reported7Reported6Reported7Reported8Reported9Reported7Reported10Reported8Reported9Reported7Reported8Reported10Reported9Reported7Reported7Reported8Reported8Reported6Reported6Reported10Reported11Reported9Reported7Reported6Reported
Mean wave power(kW/m)-------------------------------
Mean wind directionNNEconcentration 95%NNWconcentration 87%WNWconcentration 92%NNWconcentration 98%NNWconcentration 99%NWconcentration 67%NWconcentration 88%NNWconcentration 98%Wconcentration 82%Wconcentration 84%WNWconcentration 97%Wconcentration 66%SWconcentration 98%WSWconcentration 98%SSWconcentration 91%WSWconcentration 96%SSWconcentration 96%SSWconcentration 97%WSWconcentration 97%SWconcentration 83%SWconcentration 98%SSWconcentration 96%WNWconcentration 78%Nconcentration 98%NNEconcentration 94%Wconcentration 94%WNWconcentration 91%NWconcentration 98%NNWconcentration 99%WNWconcentration 92%Nconcentration 97%
Mean wind speed (mph)14153029331528202223292127242718232725202520322614213635302221
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.

Which wave period is shown?

The table shows the best period measurement supplied for each observation. It is not necessarily the energy period used to calculate wave power.

Tp
Peak period: the period at the strongest spectral peak.
Tavg
The provider's average wave period.
Tm02
A mean period calculated from the wave spectrum.
Tz
Mean zero-crossing period.
Reported
A legacy value whose period type was not recorded.
Mixed
A daily or monthly mean containing more than one period type.

Wave power needs a genuine energy period (Te). SurfHog does not substitute Tp, Tavg, Tm02 or Tz when Te is missing.

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 UK Met Office.

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