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St Mary's Sound wave buoy daily means for Mar 2017

Daily means from the St Mary's Sound wave buoy for Mar 2017, 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 4.9 ft (10th–90th percentile 2.9–7.7 ft), while the reported wave period averaged 8.9 seconds (10th–90th percentile 6–13 seconds). Mean water temperature was 10.3°C (10th–90th percentile 10.2–10.4°C). 11 of 2,972 checked values (0.4%) were excluded by quality control.

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

Typical Significant Wave Height

4.9ft
Mean: 5.1 ft
P10–P90: 2.9 — 7.7 ft
Recorded extremes

1.7 — 10.7 ft

Available for 742 of 743 hourly samples

Mean Observed Wave Period

8.9secs
P10–P90: 6 — 13secs
Recorded extremes

4 — 18secs

Available for 733 of 743 hourly samples

Observed Wave Direction

SW

Circular concentration: 51%

Mean Water Temperature

10.3°C
P10–P90: 10.2 — 10.4°C
Recorded extremes

10.1 — 10.7°C

Chart showing grouped wave observations for St Mary's Sound. 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 St Mary's Sound wave buoy

St Mary's Sound station lies between St Mary's and St Agnes in the Isles of Scilly. The National Network first deployed a Datawell Directional WaveRider here in May 2014, establishing a nearshore record for an archipelago exposed to Atlantic swell and important to local navigation and coastal management.

Its current data source reports wave height, wave period, wave direction, directional spread and sea temperature.

Metrics are rows; days run left to right.
St Mary's Sound wave buoy daily means Mar 2017Last observation shown
Metric
Mean significant wave height (ft)5686765644434332344565455QC rejected56887
Mean maximum wave height (ft)-------------------------------
Mean peak period (s)-------------------------------
Mean zero-crossing period (s)-------------------------------
Mean reported period (s)8879101098108891112131411897881177868898
Mean peak wave direction-------------------------------
Mean directional spread (°)-------------------------------
Mean reported wave directionSWconcentration 92%SWconcentration 86%Sconcentration 98%WSWconcentration 88%WSWconcentration 90%Wconcentration 80%SWconcentration 75%SWconcentration 99%WSWconcentration 83%SSWconcentration 79%SSWconcentration 82%Wconcentration 76%Wconcentration 79%WNWconcentration 62%WNWconcentration 55%Variableconcentration 24%NWconcentration 71%WNWconcentration 83%WNWconcentration 72%SWconcentration 89%WSWconcentration 83%SWconcentration 94%NWconcentration 52%Econcentration 100%ESEconcentration 100%ESEconcentration 98%ESEconcentration 92%SSWconcentration 96%SSWconcentration 99%SSWconcentration 99%SSWconcentration 98%
Mean water temperature(°C)10.310.310.310.210.210.210.210.210.310.310.310.310.310.310.410.410.310.310.410.410.410.410.310.310.310.310.310.410.410.410.5

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.

Observation data source

Learn how SurfHog combines, checks and summarizes observations in the data and methodology notes.

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