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Sevenstones wave buoy daily means for Sep 2013

Daily means from the Sevenstones wave buoy for Sep 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

717 wave-buoy observations covered all 30 days. Typical wave height was 3.9 ft (10th–90th percentile 2.6–7.2 ft), while the reported wave period averaged 7.6 seconds (10th–90th percentile 6–9 seconds). Typical wind was 15 mph (10th–90th percentile 6.9–27.7 mph) and mean water temperature was 15.3°C (10th–90th percentile 14.3–16.6°C). All 3,585 checked values passed quality control. Across 3 comparable years, mean wave height was below the same-month mean of 5.5 ft and mean wave period was below the same-month mean of 8 seconds.

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

Typical Significant Wave Height

3.9ft
Mean: 4.6 ft
P10–P90: 2.6 — 7.2 ft
Recorded extremes

1.6 — 11.5 ft

Mean Observed Wave Period

7.6secs
P10–P90: 6 — 9secs
Recorded extremes

5 — 11secs

Typical Observed Wind

Variable, 15mph
Mean: 16.7 mph
P10–P90: 6.9 — 27.7 mph
Recorded extremes

2.2 — 38 mph

Circular concentration: 13%

Mean Water Temperature

15.3°C
P10–P90: 14.3 — 16.6°C
Recorded extremes

13.8 — 17.9°C

Compared With Previous Septembers

Historical baseline from 1,976 observations across 3 years.

Wave Height
4.6ft
0.9ft below mean
Historical mean 5.5ft
Wave Period
7.6s
0.4s below mean
Historical mean 8s
Water Temperature
15.3°C
0.1°C below mean
Historical mean 15.4°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 Sep 2013Last observation shown
Metric
Mean significant wave height (ft)5333345354344461098554554444543
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)9889877676667888887881088987877
Mean peak wave direction------------------------------
Mean wave direction------------------------------
Mean directional spread (°)------------------------------
Mean wind directionNNWconcentration 90%NWconcentration 96%Econcentration 88%SEconcentration 98%NWconcentration 52%NWconcentration 73%NWconcentration 78%WSWconcentration 80%NWconcentration 82%NNWconcentration 96%NNWconcentration 90%WNWconcentration 96%WNWconcentration 74%Nconcentration 97%Wconcentration 84%NWconcentration 99%WNWconcentration 96%NWconcentration 92%Wconcentration 84%Variableconcentration 28%SWconcentration 85%SEconcentration 93%ESEconcentration 98%ESEconcentration 91%SEconcentration 94%SEconcentration 82%Econcentration 99%Econcentration 98%ESEconcentration 89%SEconcentration 98%
Mean wind speed (mph)9107141316121619181515171323322923211011122614111126201720
Mean water temperature(°C)16.616.717.316.816.516.015.615.315.215.014.814.915.114.814.714.614.314.214.114.114.514.714.514.715.115.515.315.515.815.8

Swipe sideways to see more days.

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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