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Sevenstones wave buoy daily means for Apr 2014

Daily means from the Sevenstones wave buoy for Apr 2014, 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

720 wave-buoy observations covered all 30 days. Typical wave height was 4.6 ft (10th–90th percentile 2.6–8.2 ft), while the reported wave period averaged 8.3 seconds (10th–90th percentile 7–10 seconds). Typical wind was 16.1 mph (10th–90th percentile 6.9–28.8 mph) and mean water temperature was 10.4°C (10th–90th percentile 9.8–11°C). 2 of 3,600 checked values (0.1%) were excluded by quality control. Across 4 comparable years, mean wave height was below the same-month mean of 5.8 ft and mean wave period was the same as the same-month mean of 8.3 seconds.

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

Typical Significant Wave Height

4.6ft
Mean: 5.2 ft
P10–P90: 2.6 — 8.2 ft
Recorded extremes

1.6 — 19 ft

Available for 718 of 720 hourly samples

Mean Observed Wave Period

8.3secs
P10–P90: 7 — 10secs
Recorded extremes

6 — 11secs

Typical Observed Wind

Variable, 16.1mph
Mean: 17 mph
P10–P90: 6.9 — 28.8 mph
Recorded extremes

0 — 43.7 mph

Circular concentration: 15%

Mean Water Temperature

10.4°C
P10–P90: 9.8 — 11°C
Recorded extremes

9.5 — 12.3°C

Compared With Previous Aprils

Historical baseline from 2,867 observations across 4 years.

Wave Height
5.2ft
0.6ft below mean
Historical mean 5.8ft
Wave Period
8.3s
In line with the historical mean
Historical mean 8.3s
Water Temperature
10.4°C
0.2°C above mean
Historical mean 10.2°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 Apr 2014Last observation shown
Metric
Mean significant wave height (ft)6454588864446543233453565QC rejected10434
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)9898788999899976898788910998789
Mean peak wave direction------------------------------
Mean wave direction------------------------------
Mean directional spread (°)------------------------------
Mean wind directionESEconcentration 97%SEconcentration 93%Sconcentration 89%SSWconcentration 91%SSWconcentration 96%SSWconcentration 87%WSWconcentration 59%WNWconcentration 99%Wconcentration 97%WNWconcentration 96%Nconcentration 91%Wconcentration 97%NNWconcentration 94%NNEconcentration 85%ESEconcentration 94%SEconcentration 98%NWconcentration 50%NEconcentration 77%Econcentration 95%NNEconcentration 90%SEconcentration 97%SSWconcentration 81%SSWconcentration 95%SSEconcentration 85%SSEconcentration 91%SWconcentration 86%NWconcentration 94%Nconcentration 66%SSWconcentration 31%Sconcentration 84%
Mean wind speed (mph)231511162122242188141516172321101116192113171319362911614
Mean water temperature(°C)9.59.79.910.09.99.99.99.910.410.710.610.410.410.210.110.110.310.310.410.310.410.610.911.011.010.710.811.111.311.0

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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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