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Sevenstones wave buoy daily means for Feb 2018

Daily means from the Sevenstones wave buoy for Feb 2018, 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

667 wave-buoy observations covered all 28 days. Typical wave height was 8.5 ft (10th–90th percentile 4.8–13.1 ft), while the reported wave period averaged 8.8 seconds (10th–90th percentile 7–11 seconds). Typical wind was 26.4 mph (10th–90th percentile 16.1–36.9 mph) and mean water temperature was 9.6°C (10th–90th percentile 9.1–10°C). 1 of 3,335 checked values (0%) were excluded by quality control. Across 7 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 9.1 seconds.

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

Typical Significant Wave Height

8.5ft
Mean: 8.7 ft
P10–P90: 4.8 — 13.1 ft
Recorded extremes

3 — 19.4 ft

Available for 666 of 667 hourly samples

Mean Observed Wave Period

8.8secs
P10–P90: 7 — 11secs
Recorded extremes

6 — 13secs

Typical Observed Wind

Variable, 26.4mph
Mean: 27 mph
P10–P90: 16.1 — 36.9 mph
Recorded extremes

10.3 — 48.3 mph

Circular concentration: 20%

Mean Water Temperature

9.6°C
P10–P90: 9.1 — 10°C
Recorded extremes

8.2 — 10.3°C

Compared With Previous Februarys

Historical baseline from 4,660 observations across 7 years.

Wave Height
8.7ft
0.8ft below mean
Historical mean 9.5ft
Wave Period
8.8s
0.3s below mean
Historical mean 9.1s
Water Temperature
9.6°C
In line with the historical mean
Historical mean 9.6°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 Feb 2018Last observation shown
Metric
Mean significant wave height (ft)1398105810811101310131115127781085557657
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)98789910999910991111991010119888766
Mean peak wave direction----------------------------
Mean wave direction----------------------------
Mean directional spread (°)----------------------------
Mean wind directionNNWconcentration 95%NNWconcentration 87%NNWconcentration 80%NEconcentration 90%ENEconcentration 92%Nconcentration 98%NNWconcentration 83%SWconcentration 87%NWconcentration 92%WSWconcentration 91%NWconcentration 99%WSWconcentration 77%WNWconcentration 59%SSWconcentration 86%Wconcentration 95%SSWconcentration 83%WSWconcentration 76%WNWconcentration 98%NWconcentration 97%Nconcentration 97%Econcentration 82%Econcentration 98%ESEconcentration 97%ESEconcentration 95%ESEconcentration 98%Econcentration 93%ENEconcentration 98%ENEconcentration 96%
Mean wind speed (mph)36243630202721273028322630302822212119281921282732322736
Mean water temperature(°C)10.110.110.09.99.79.69.69.89.69.89.79.69.69.69.79.69.69.79.79.79.69.59.49.39.29.18.78.4

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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