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

Daily means from the St Mary's Sound wave buoy for Jun 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 2.4 ft (10th–90th percentile 1.3–4.8 ft), while mean average of more than one wave period type was 7.6 seconds (10th–90th percentile 5.2–10.3 seconds). Mean water temperature was 14.4°C (10th–90th percentile 13.4–16.1°C). 24 of 5,749 checked values (0.4%) were excluded by quality control. Across 6 comparable years, mean wave height was above the same-month mean of 2.7 ft and mean wave period was above the same-month mean of 6.7 seconds.

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

Typical Significant Wave Height

2.4ft
Mean: 2.8 ft
P10–P90: 1.3 — 4.8 ft
Recorded extremes

0.9 — 10.2 ft

Mean Observed Wave Period

7.6secs
P10–P90: 5.2 — 10.3secs
Recorded extremes

2.9 — 18.2secs

Available for 718 of 720 hourly samples

Observed Wave Direction

SSW

Circular concentration: 40%

Mean Water Temperature

14.4°C
P10–P90: 13.4 — 16.1°C
Recorded extremes

12.9 — 17.6°C

Compared With Previous Junes

Historical baseline from 4,315 observations across 6 years.

Wave Height
2.8ft
0.1ft above mean
Historical mean 2.7ft
Wave Period
7.6s
0.9s above mean
Historical mean 6.7s
Water Temperature
14.4°C
0.8°C above mean
Historical mean 13.6°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 Jun 2023Last observation shown
Metric
Mean significant wave height (ft)443334485332111222222133333223
Mean maximum wave height (ft)6754567129543222333332245444334
Mean peak period (s)6765666761087779910107651587788997
Mean zero-crossing period (s)554444455665666544444545454444
Mean energy period (s)------------------------------
Mean reported period (s)554444455665666544444545454444
Mean wave power, kilowatts per metre------------------------------
Mean peak wave directionESEconcentration 99%ESEconcentration 99%ESEconcentration 99%ESEconcentration 98%ESEconcentration 98%ESEconcentration 99%ESEconcentration 99%ESEconcentration 99%ESEconcentration 83%SSWconcentration 100%SSWconcentration 100%SSWconcentration 100%SWconcentration 99%SWconcentration 99%WSWconcentration 97%WSWconcentration 84%Wconcentration 76%WSWconcentration 91%SWconcentration 96%SSWconcentration 84%SSWconcentration 95%SSWconcentration 99%SWconcentration 86%SWconcentration 81%WSWconcentration 82%Wconcentration 90%WNWconcentration 79%NWconcentration 95%NWconcentration 96%Wconcentration 81%
Mean directional spread (°)22.021.126.626.924.624.223.819.226.522.726.331.334.633.147.647.149.850.537.738.034.227.832.443.646.749.651.752.450.444.6
Mean reported wave directionESEconcentration 99%ESEconcentration 99%ESEconcentration 99%ESEconcentration 98%ESEconcentration 98%ESEconcentration 99%ESEconcentration 99%ESEconcentration 99%ESEconcentration 83%SSWconcentration 100%SSWconcentration 100%SSWconcentration 100%SWconcentration 99%SWconcentration 99%WSWconcentration 96%WSWconcentration 85%Wconcentration 82%WSWconcentration 92%SWconcentration 96%SSWconcentration 90%SSWconcentration 96%SSWconcentration 100%SWconcentration 85%SWconcentration 81%WSWconcentration 78%Wconcentration 90%WNWconcentration 80%NWconcentration 92%NWconcentration 94%WNWconcentration 82%
Mean water temperature(°C)13.613.413.413.513.513.513.513.513.613.613.713.814.014.214.814.114.014.014.114.614.514.714.515.615.216.515.916.216.615.8

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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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