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Sevenstones wave buoy daily means for Dec 2015

Daily means from the Sevenstones wave buoy for Dec 2015, 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

709 wave-buoy observations covered all 31 days. Typical wave height was 11.2 ft (10th–90th percentile 7.9–16.7 ft), while the reported wave period averaged 9 seconds (10th–90th percentile 8–10 seconds). Typical wind was 30 mph (10th–90th percentile 21.4–39.1 mph). 38 of 2,836 checked values (1.3%) were excluded by quality control. Across 5 comparable years, mean wave height was above the same-month mean of 8.9 ft and mean wave period was above the same-month mean of 8.6 seconds.

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

Typical Significant Wave Height

11.2ft
Mean: 11.7 ft
P10–P90: 7.9 — 16.7 ft
Recorded extremes

4.6 — 23 ft

Available for 692 of 709 hourly samples

Mean Observed Wave Period

9secs
P10–P90: 8 — 10secs
Recorded extremes

6 — 14secs

Available for 691 of 709 hourly samples

Typical Observed Wind

SW, 30mph
Mean: 30.2 mph
P10–P90: 21.4 — 39.1 mph
Recorded extremes

0 — 49.4 mph

Circular concentration: 84%

Available for 706 of 709 hourly samples

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 709 hourly samples

Compared With Previous Decembers

Historical baseline from 3,680 observations across 5 years.

Wave Height
11.7ft
2.8ft above mean
Historical mean 8.9ft
Wave Period
9s
0.4s above mean
Historical mean 8.6s
Water Temperature
–
Not enough comparable data
Historical mean 11.4°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 Dec 2015Last observation shown
Metric
Mean significant wave height (ft)121399191711111212109788109912121213QC rejectedQC rejected1212910131915
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)998810119999109888989910991110988891010
Mean peak wave direction-------------------------------
Mean wave direction-------------------------------
Mean directional spread (°)-------------------------------
Mean wind directionSWconcentration 95%SSWconcentration 99%SSWconcentration 62%WSWconcentration 92%SWconcentration 100%SWconcentration 98%Sconcentration 98%WSWconcentration 89%SWconcentration 97%WSWconcentration 87%Wconcentration 73%SWconcentration 96%Sconcentration 84%Sconcentration 94%Sconcentration 91%SWconcentration 91%SWconcentration 95%SSWconcentration 96%SSWconcentration 97%SWconcentration 97%SWconcentration 90%SWconcentration 96%SWconcentration 89%WSWconcentration 86%SSWconcentration 97%SSWconcentration 99%SSWconcentration 90%Sconcentration 86%SSWconcentration 93%SSWconcentration 91%WSWconcentration 90%
Mean wind speed (mph)26313430382831303126173020262727282732282934333433373133343535
Mean water temperature(°C)-------------------------------

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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