Skip to content
Surfhog home
Menu

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

Daily means from the St Mary's Sound wave buoy for Oct 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

1,487 wave-buoy observations covered all 31 days. Typical wave height was 4.1 ft (10th–90th percentile 2.4–8.4 ft), while mean average of more than one wave period type was 8.5 seconds (10th–90th percentile 5.6–11.2 seconds). Mean water temperature was 14.6°C (10th–90th percentile 13.8–15.2°C). 11 of 5,948 checked values (0.2%) were excluded by quality control. Across 7 comparable years, mean wave height was above the same-month mean of 4.6 ft and mean wave period was above the same-month mean of 7.6 seconds.

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

Typical Significant Wave Height

4.1ft
Mean: 4.8 ft
P10–P90: 2.4 — 8.4 ft
Recorded extremes

1.8 — 12.8 ft

Mean Observed Wave Period

8.5secs
P10–P90: 5.6 — 11.2secs
Recorded extremes

3.7 — 15.4secs

Available for 744 of 745 hourly samples

Observed Wave Direction

SW

Circular concentration: 69%

Mean Water Temperature

14.6°C
P10–P90: 13.8 — 15.2°C
Recorded extremes

13.6 — 16.2°C

Compared With Previous Octobers

Historical baseline from 4,603 observations across 7 years.

Wave Height
4.8ft
0.2ft above mean
Historical mean 4.6ft
Wave Period
8.5s
0.9s above mean
Historical mean 7.6s
Water Temperature
14.6°C
0.4°C above mean
Historical mean 14.2°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 Oct 2023Last observation shown
Metric
Mean significant wave height (ft)32333333234374381097654545667976
Mean maximum wave height (ft)54445445446512641215131110767689101114119
Mean peak period (s)89997991110866910877109121176799991098
Mean zero-crossing period (s)5555454564456655666665556666665
Mean energy period (s)-------------------------------
Mean reported period (s)5555454564446655666665556666665
Mean wave power, kilowatts per metre-------------------------------
Mean peak wave directionSWconcentration 89%Wconcentration 71%WNWconcentration 89%WNWconcentration 76%Wconcentration 67%WNWconcentration 78%WNWconcentration 88%WSWconcentration 96%WSWconcentration 96%SWconcentration 99%SWconcentration 96%SSWconcentration 98%SSWconcentration 99%SWconcentration 100%Sconcentration 67%ESEconcentration 99%ESEconcentration 99%Sconcentration 84%SSWconcentration 99%WSWconcentration 77%WNWconcentration 86%SWconcentration 91%Sconcentration 94%SSWconcentration 92%SSWconcentration 98%SWconcentration 99%SWconcentration 90%SSWconcentration 97%SSWconcentration 99%SSWconcentration 99%SSWconcentration 99%
Mean directional spread (°)47.651.053.558.443.449.953.946.948.743.633.636.627.634.537.026.827.230.125.344.659.547.438.443.030.038.248.740.035.737.537.3
Mean reported wave directionSWconcentration 90%Wconcentration 72%NWconcentration 87%WNWconcentration 71%Wconcentration 65%WNWconcentration 81%WNWconcentration 86%WSWconcentration 96%WSWconcentration 96%SWconcentration 99%SWconcentration 97%SSWconcentration 98%SSWconcentration 99%SWconcentration 100%Sconcentration 71%ESEconcentration 99%ESEconcentration 96%Sconcentration 85%SSWconcentration 99%WSWconcentration 84%WNWconcentration 88%SWconcentration 89%Sconcentration 94%SSWconcentration 92%SSWconcentration 98%SWconcentration 98%SWconcentration 94%SSWconcentration 96%SSWconcentration 99%SSWconcentration 99%SSWconcentration 99%
Mean water temperature(°C)15.014.914.814.814.915.015.415.415.315.015.115.014.814.814.714.514.514.514.514.414.414.314.314.214.214.013.913.813.813.713.7

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 Regional Coastal Monitoring Programme.

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

› Wave Buoy List