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Sevenstones wave buoy daily means for Jan 2019

Daily means from the Sevenstones wave buoy for Jan 2019, 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 6.2 ft (10th–90th percentile 3–11.5 ft), while the reported wave period averaged 8.6 seconds (10th–90th percentile 7–10 seconds). Typical wind was 20.8 mph (10th–90th percentile 9.2–33.3 mph) and mean water temperature was 10.8°C (10th–90th percentile 10.3–11.1°C). 1 of 3,715 checked values (0%) were excluded by quality control. Across 8 comparable years, mean wave height was below the same-month mean of 9.5 ft and mean wave period was below the same-month mean of 9 seconds.

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

Typical Significant Wave Height

6.2ft
Mean: 6.8 ft
P10–P90: 3 — 11.5 ft
Recorded extremes

1.6 — 25.3 ft

Available for 742 of 743 hourly samples

Mean Observed Wave Period

8.6secs
P10–P90: 7 — 10secs
Recorded extremes

6 — 13secs

Typical Observed Wind

NW, 20.8mph
Mean: 20.9 mph
P10–P90: 9.2 — 33.3 mph
Recorded extremes

3.4 — 55.3 mph

Circular concentration: 45%

Mean Water Temperature

10.8°C
P10–P90: 10.3 — 11.1°C
Recorded extremes

10.1 — 11.3°C

Compared With Previous Januarys

Historical baseline from 5,884 observations across 8 years.

Wave Height
6.8ft
2.7ft below mean
Historical mean 9.5ft
Wave Period
8.6s
0.4s below mean
Historical mean 9s
Water Temperature
10.8°C
0.3°C above mean
Historical mean 10.5°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 2019Last observation shown
Metric
Mean significant wave height (ft)53343QC rejected544235865610711781111869QC rejected108107
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)988891297789788979811910910988108898
Mean peak wave direction-------------------------------
Mean wave direction-------------------------------
Mean directional spread (°)-------------------------------
Mean wind directionNNWconcentration 85%Econcentration 79%ESEconcentration 88%SEconcentration 96%Sconcentration 90%Wconcentration 92%Wconcentration 99%NNWconcentration 92%NNEconcentration 91%NNEconcentration 63%NNWconcentration 95%NWconcentration 97%WNWconcentration 98%NNWconcentration 88%SWconcentration 93%Wconcentration 75%NNWconcentration 59%SWconcentration 77%NWconcentration 79%Nconcentration 96%WNWconcentration 62%NWconcentration 95%NNWconcentration 88%WNWconcentration 74%WNWconcentration 97%Wconcentration 95%NWconcentration 98%NNWconcentration 93%WNWconcentration 55%NWconcentration 62%ESEconcentration 73%
Mean wind speed (mph)111818171392122199172632171927212319202128231622343723232023
Mean water temperature(°C)11.311.211.111.011.011.111.111.111.010.911.111.011.010.910.910.910.710.710.810.710.710.510.510.610.710.610.410.410.310.210.1

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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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