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St Mary's Sound wave buoy daily means for Nov 2023

Daily means from the St Mary's Sound wave buoy for Nov 2023, 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

1,438 wave-buoy observations covered all 30 days. Typical wave height was 5.4 ft (10th–90th percentile 2–8.6 ft), while mean average of more than one wave period type was 8.9 seconds (10th–90th percentile 5.9–11.8 seconds). Mean water temperature was 12.8°C (10th–90th percentile 12.5–13.3°C). 14 of 5,749 checked values (0.2%) were excluded by quality control. Across 7 comparable years, mean wave height was above the same-month mean of 4.9 ft and mean wave period was above the same-month mean of 7.3 seconds.

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

Typical Significant Wave Height

5.4ft
Mean: 5.3 ft
P10–P90: 2 — 8.6 ft
Recorded extremes

1.4 — 14.2 ft

Mean Observed Wave Period

8.9secs
P10–P90: 5.9 — 11.8secs
Recorded extremes

3.6 — 15.4secs

Available for 719 of 720 hourly samples

Observed Wave Direction

SW

Circular concentration: 58%

Mean Water Temperature

12.8°C
P10–P90: 12.5 — 13.3°C
Recorded extremes

12.1 — 13.7°C

Compared With Previous Novembers

Historical baseline from 5,029 observations across 7 years.

Wave Height
5.3ft
0.4ft above mean
Historical mean 4.9ft
Wave Period
8.9s
1.6s above mean
Historical mean 7.3s
Water Temperature
12.8°C
0.2°C below mean
Historical mean 13°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, wave power and sea temperature.

Metrics are rows; days run left to right.
St Mary's Sound wave buoy daily means Nov 2023Last observation shown
Metric
Mean significant wave height (ft)109687548765786QC rejected757753222233327
Mean maximum wave height (ft)1614913118613119711131071181111843433554310
Mean peak period (s)1013119111099910899998889108711119577107
Mean zero-crossing period (s)676666566656666655654455445565
Mean energy period (s)------------------------------
Mean reported period (s)676666566656666655654455445565
Mean wave power, kilowatts per metre------------------------------
Mean peak wave directionSSWconcentration 99%SSWconcentration 99%WSWconcentration 90%SSWconcentration 96%SWconcentration 98%WSWconcentration 87%Wconcentration 77%SSWconcentration 99%SWconcentration 91%Wconcentration 86%SSWconcentration 55%SSWconcentration 92%SSWconcentration 99%SWconcentration 94%WSWconcentration 86%SSEconcentration 86%SSWconcentration 96%SSWconcentration 99%SWconcentration 99%Wconcentration 93%Nconcentration 69%Variableconcentration 11%NWconcentration 95%NWconcentration 71%WSWconcentration 38%Sconcentration 95%SSWconcentration 57%Variableconcentration 7%WSWconcentration 73%Econcentration 92%
Mean directional spread (°)31.935.651.436.541.251.152.032.243.354.246.534.534.643.652.035.643.235.043.452.360.853.853.956.156.832.547.754.652.526.4
Mean reported wave directionSSWconcentration 99%SSWconcentration 99%WSWconcentration 89%SSWconcentration 96%SWconcentration 97%WSWconcentration 85%Wconcentration 79%SSWconcentration 99%SWconcentration 91%Wconcentration 86%SSWconcentration 59%SSWconcentration 92%SSWconcentration 98%SWconcentration 92%SWconcentration 87%SSEconcentration 87%SSWconcentration 95%SSWconcentration 99%SWconcentration 98%Wconcentration 92%Nconcentration 69%Variableconcentration 6%NWconcentration 95%NWconcentration 67%Variableconcentration 18%Sconcentration 95%SSWconcentration 56%Variableconcentration 3%WSWconcentration 78%Econcentration 92%
Mean water temperature(°C)13.613.513.413.313.213.113.113.113.012.812.812.812.812.812.812.812.812.812.812.712.712.612.612.612.612.612.512.512.412.4

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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 Regional Coastal Monitoring Programme.

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

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