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Sevenstones wave buoy daily means for Jun 2017

Daily means from the Sevenstones wave buoy for Jun 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

718 wave-buoy observations covered all 30 days. Typical wave height was 5.2 ft (10th–90th percentile 2.3–9.2 ft), while the reported wave period averaged 7.9 seconds (10th–90th percentile 6–9 seconds). Typical wind was 18.3 mph (10th–90th percentile 8.1–30 mph) and mean water temperature was 14.8°C (10th–90th percentile 13.4–16.6°C). All 3,590 checked values passed quality control. Across 7 comparable years, mean wave height was above the same-month mean of 4.2 ft and mean wave period was above the same-month mean of 7.4 seconds.

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

Typical Significant Wave Height

5.2ft
Mean: 5.6 ft
P10–P90: 2.3 — 9.2 ft
Recorded extremes

1 — 17.1 ft

Mean Observed Wave Period

7.9secs
P10–P90: 6 — 9secs
Recorded extremes

5 — 12secs

Typical Observed Wind

WSW, 18.3mph
Mean: 18.7 mph
P10–P90: 8.1 — 30 mph
Recorded extremes

3.4 — 48.3 mph

Circular concentration: 45%

Mean Water Temperature

14.8°C
P10–P90: 13.4 — 16.6°C
Recorded extremes

12.9 — 17.6°C

Compared With Previous Junes

Historical baseline from 4,929 observations across 7 years.

Wave Height
5.6ft
1.4ft above mean
Historical mean 4.2ft
Wave Period
7.9s
0.5s above mean
Historical mean 7.4s
Water Temperature
14.8°C
1.1°C above mean
Historical mean 13.7°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 Jun 2017Last observation shown
Metric
Mean significant wave height (ft)47569QC rejected7667118457754432256532359
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)810888887881098910989987678777678
Mean peak wave direction------------------------------
Mean wave direction------------------------------
Mean directional spread (°)------------------------------
Mean wind directionSconcentration 98%NWconcentration 50%Wconcentration 95%WSWconcentration 91%SWconcentration 76%WNWconcentration 98%WSWconcentration 80%SSWconcentration 95%SWconcentration 89%SSWconcentration 97%WSWconcentration 96%Wconcentration 99%SSWconcentration 50%SSEconcentration 39%WSWconcentration 88%Wconcentration 98%NNWconcentration 41%NEconcentration 93%ENEconcentration 86%NEconcentration 90%Sconcentration 51%Wconcentration 95%WSWconcentration 96%Wconcentration 95%Wconcentration 96%SSWconcentration 62%SWconcentration 76%NWconcentration 95%NNWconcentration 90%NNWconcentration 99%
Mean wind speed (mph)15131818323626272227241988211571211121519222121611182731
Mean water temperature(°C)13.614.014.114.013.913.113.313.413.613.613.713.914.214.914.814.915.616.116.416.916.816.716.216.215.915.816.115.414.313.5

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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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