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Sevenstones wave buoy daily means for Jan 2015

Daily means from the Sevenstones wave buoy for Jan 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

743 wave-buoy observations covered all 31 days. Typical wave height was 10.5 ft (10th–90th percentile 5.6–16.7 ft), while the reported wave period averaged 9.2 seconds (10th–90th percentile 7–11 seconds). Typical wind was 27.7 mph (10th–90th percentile 13.9–40.3 mph) and mean water temperature was 10.9°C (10th–90th percentile 10.3–11.5°C). 3 of 3,715 checked values (0.1%) were excluded by quality control. Across 4 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 9 seconds.

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

Typical Significant Wave Height

10.5ft
Mean: 10.9 ft
P10–P90: 5.6 — 16.7 ft
Recorded extremes

3.6 — 24.6 ft

Available for 740 of 743 hourly samples

Mean Observed Wave Period

9.2secs
P10–P90: 7 — 11secs
Recorded extremes

6 — 13secs

Typical Observed Wind

W, 27.7mph
Mean: 27.8 mph
P10–P90: 13.9 — 40.3 mph
Recorded extremes

2.2 — 55.3 mph

Circular concentration: 62%

Mean Water Temperature

10.9°C
P10–P90: 10.3 — 11.5°C
Recorded extremes

9.7 — 11.6°C

Compared With Previous Januarys

Historical baseline from 2,948 observations across 4 years.

Wave Height
10.9ft
2ft above mean
Historical mean 8.9ft
Wave Period
9.2s
0.2s above mean
Historical mean 9s
Water Temperature
10.9°C
0.5°C above mean
Historical mean 10.4°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 Jan 2015Last observation shown
Metric
Mean significant wave height (ft)81010751112141515131514182214966101385666711161414
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)7109981091010101010101011111079101098898981098
Mean peak wave direction-------------------------------
Mean wave direction-------------------------------
Mean directional spread (°)-------------------------------
Mean wind directionSWconcentration 97%WNWconcentration 70%Wconcentration 69%Sconcentration 59%SSWconcentration 97%Wconcentration 77%SWconcentration 98%Wconcentration 88%Wconcentration 97%WNWconcentration 86%Wconcentration 89%WSWconcentration 97%Wconcentration 94%WSWconcentration 79%Wconcentration 98%NWconcentration 90%Wconcentration 93%Nconcentration 93%Variableconcentration 21%WSWconcentration 70%Nconcentration 94%NNEconcentration 79%SWconcentration 85%NNWconcentration 87%WSWconcentration 98%NWconcentration 77%WNWconcentration 90%WNWconcentration 90%NWconcentration 97%NWconcentration 98%NNWconcentration 99%
Mean wind speed (mph)33203013212433303736343430394021202716243011222020231934393742
Mean water temperature(°C)11.611.511.511.511.511.411.411.511.511.411.111.211.010.810.910.710.610.610.510.510.410.410.510.510.610.610.510.510.210.29.9

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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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