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Sevenstones wave buoy daily means for Aug 2013

Daily means from the Sevenstones wave buoy for Aug 2013, 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

743 wave-buoy observations covered all 31 days. Typical wave height was 3.6 ft (10th–90th percentile 2–5.9 ft), while the reported wave period averaged 7.1 seconds (10th–90th percentile 6–8 seconds). Typical wind was 13.9 mph (10th–90th percentile 6.9–21.9 mph) and mean water temperature was 17.4°C (10th–90th percentile 16.1–18.4°C). All 3,715 checked values passed quality control. Across 3 comparable years, mean wave height was below the same-month mean of 4.2 ft and mean wave period was above the same-month mean of 7 seconds.

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

Typical Significant Wave Height

3.6ft
Mean: 3.8 ft
P10–P90: 2 — 5.9 ft
Recorded extremes

1.3 — 9.8 ft

Mean Observed Wave Period

7.1secs
P10–P90: 6 — 8secs
Recorded extremes

5 — 10secs

Typical Observed Wind

W, 13.9mph
Mean: 14.5 mph
P10–P90: 6.9 — 21.9 mph
Recorded extremes

2.2 — 42.5 mph

Circular concentration: 44%

Mean Water Temperature

17.4°C
P10–P90: 16.1 — 18.4°C
Recorded extremes

14.7 — 18.7°C

Compared With Previous Augusts

Historical baseline from 2,027 observations across 3 years.

Wave Height
3.8ft
0.4ft below mean
Historical mean 4.2ft
Wave Period
7.1s
0.1s above mean
Historical mean 7s
Water Temperature
17.4°C
1.4°C above mean
Historical mean 16°C

Chart showing grouped wave observations for Sevenstones. 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 Sevenstones wave buoy

Sevenstones Lightship (WMO 62107) is a UK Met Office station west of Land's End, near the Seven Stones reef in the Western Approaches. Its exposed offshore position shows Atlantic systems before they reach Cornwall and the western English Channel and provides context for a notoriously hazardous shipping area.

Its current data source reports wave height, wave period, wave direction, directional spread, wind conditions, sea temperature, separate swell and wind-sea components and wave spectra.

Metrics are rows; days run left to right.
Sevenstones wave buoy daily means Aug 2013Last observation shown
Metric
Mean significant wave height (ft)5445532345333234565544275432235
Mean maximum wave height (ft)-------------------------------
Mean maximum crest height (ft)-------------------------------
Mean maximum trough height (ft)-------------------------------
Mean peak period (s)-------------------------------
Mean average period (s)-------------------------------
Mean period Tm02 (s)-------------------------------
Mean zero-crossing period (s)-------------------------------
Mean maximum wave period (s)-------------------------------
Mean reported period (s)7766767768766667788988787877888
Mean peak wave direction-------------------------------
Mean wave direction-------------------------------
Mean directional spread (°)-------------------------------
Mean wind directionSconcentration 99%SWconcentration 96%WSWconcentration 92%SSWconcentration 99%WNWconcentration 59%Variableconcentration 20%NEconcentration 68%WSWconcentration 66%NWconcentration 95%WSWconcentration 88%WNWconcentration 89%NWconcentration 96%WNWconcentration 89%SWconcentration 96%SWconcentration 97%WNWconcentration 68%SWconcentration 94%Wconcentration 87%WNWconcentration 95%SSWconcentration 89%SSWconcentration 76%ENEconcentration 85%SWconcentration 43%NWconcentration 76%Nconcentration 86%Nconcentration 98%Nconcentration 97%Nconcentration 95%Wconcentration 93%Wconcentration 91%Nconcentration 99%
Mean wind speed (mph)191719242178131912131711161815211513887111919131210111418
Mean water temperature(°C)18.518.418.418.117.717.717.917.417.617.517.818.118.118.118.418.317.316.616.817.117.617.617.516.415.916.015.816.116.917.416.4

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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 Met Office Marine observations.

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

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