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Sevenstones wave buoy daily means for Mar 2020

Daily means from the Sevenstones wave buoy for Mar 2020, 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

737 wave-buoy observations covered all 31 days. Typical wave height was 8.2 ft (10th–90th percentile 4.6–13.5 ft), while the reported wave period averaged 8.7 seconds (10th–90th percentile 7–10 seconds). Typical wind was 26.4 mph (10th–90th percentile 13.9–36.9 mph) and mean water temperature was 9.5°C (10th–90th percentile 9.3–9.6°C). All 3,685 checked values passed quality control. Across 10 comparable years, mean wave height was above the same-month mean of 6.8 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

8.2ft
Mean: 8.6 ft
P10–P90: 4.6 — 13.5 ft
Recorded extremes

3 — 20.7 ft

Mean Observed Wave Period

8.7secs
P10–P90: 7 — 10secs
Recorded extremes

6 — 14secs

Typical Observed Wind

Variable, 26.4mph
Mean: 26.1 mph
P10–P90: 13.9 — 36.9 mph
Recorded extremes

5.8 — 51.9 mph

Circular concentration: 18%

Mean Water Temperature

9.5°C
P10–P90: 9.3 — 9.6°C
Recorded extremes

9.2 — 10.1°C

Compared With Previous Marchs

Historical baseline from 6,926 observations across 10 years.

Wave Height
8.6ft
1.8ft above mean
Historical mean 6.824ft
Wave Period
8.7s
0.1s above mean
Historical mean 8.6s
Water Temperature
9.5°C
In line with the historical mean
Historical mean 9.5°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 Mar 2020Last observation shown
Metric
Mean significant wave height (ft)1491077119141312111712998897895497645965
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)10910889910109910109899108777813101097776
Mean peak wave direction-------------------------------
Mean wave direction-------------------------------
Mean directional spread (°)-------------------------------
Mean wind directionWconcentration 89%NWconcentration 96%WNWconcentration 87%WSWconcentration 35%NNWconcentration 80%NWconcentration 98%SWconcentration 92%Wconcentration 95%WSWconcentration 90%WSWconcentration 100%WSWconcentration 94%Wconcentration 99%WSWconcentration 82%WSWconcentration 86%WNWconcentration 69%Wconcentration 59%SSWconcentration 98%SSWconcentration 57%NNEconcentration 98%NEconcentration 92%Econcentration 99%ENEconcentration 89%Econcentration 89%SSEconcentration 94%ESEconcentration 99%NEconcentration 86%NEconcentration 93%NNEconcentration 96%NEconcentration 97%NEconcentration 97%NEconcentration 98%
Mean wind speed (mph)30281922293228323133283624271917252225314423191318111831372830
Mean water temperature(°C)9.49.39.49.59.49.39.49.49.49.59.59.49.39.49.49.59.59.59.49.49.59.59.59.69.79.79.69.69.59.59.5

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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