Skip to content
Surfhog home
Menu

St Mary's Sound wave buoy daily means for Feb 2020

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

1,392 wave-buoy observations covered all 29 days. Typical wave height was 6.6 ft (10th–90th percentile 4.3–11.7 ft), while mean average of more than one wave period type was 9.6 seconds (10th–90th percentile 6.7–12.5 seconds). Mean water temperature was 10.2°C (10th–90th percentile 9.9–10.3°C). 17 of 5,535 checked values (0.3%) were excluded by quality control. Across 3 comparable years, mean wave height was above the same-month mean of 5.7 ft and mean wave period was above the same-month mean of 9.2 seconds.

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

Typical Significant Wave Height

6.6ft
Mean: 7.2 ft
P10–P90: 4.3 — 11.7 ft
Recorded extremes

2.1 — 16.8 ft

Mean Observed Wave Period

9.6secs
P10–P90: 6.7 — 12.5secs
Recorded extremes

3.9 — 22.2secs

Observed Wave Direction

SW

Circular concentration: 72%

Mean Water Temperature

10.2°C
P10–P90: 9.9 — 10.3°C
Recorded extremes

9.8 — 10.4°C

Compared With Previous Februarys

Historical baseline from 2,009 observations across 3 years.

Wave Height
7.2ft
1.5ft above mean
Historical mean 5.709ft
Wave Period
9.6s
0.4s above mean
Historical mean 9.2s
Water Temperature
10.2°C
In line with the historical mean
Historical mean 10.2°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 Feb 2020Last observation shown
Metric
Mean significant wave height (ft)676425781297696121496677777655810
Mean maximum wave height (ft)911106491112191410814101821149911111111109881215
Mean peak period (s)98109106791011101211101112108108910101011129810
Mean zero-crossing period (s)66655456766676776656666655657
Mean energy period (s)-----------------------------
Mean reported period (s)98101011779101111121111111210910891091011139811
Mean wave power, kilowatts per metre-----------------------------
Mean peak wave directionSWconcentration 78%SSWconcentration 100%SWconcentration 92%SWconcentration 93%WSWconcentration 90%SEconcentration 83%SSEconcentration 87%SWconcentration 86%SSWconcentration 100%WSWconcentration 77%Wconcentration 68%Wconcentration 42%WSWconcentration 75%SWconcentration 54%SSWconcentration 96%SSWconcentration 100%SWconcentration 97%SWconcentration 93%WSWconcentration 56%SWconcentration 98%WSWconcentration 74%WSWconcentration 75%WSWconcentration 78%WSWconcentration 76%WNWconcentration 66%NWconcentration 51%SWconcentration 96%SSWconcentration 96%SSWconcentration 100%
Mean directional spread (°)35.929.833.046.454.033.234.935.428.539.843.949.637.939.234.726.735.538.935.535.234.138.639.537.845.149.843.133.732.2
Mean reported wave directionSWconcentration 74%SSWconcentration 100%SWconcentration 88%SWconcentration 87%WSWconcentration 76%SEconcentration 84%SSEconcentration 86%SWconcentration 82%SSWconcentration 99%WSWconcentration 72%Wconcentration 66%Wconcentration 36%SWconcentration 74%SWconcentration 51%SSWconcentration 97%SSWconcentration 100%SWconcentration 93%SWconcentration 74%WSWconcentration 56%SWconcentration 99%WSWconcentration 72%SWconcentration 79%WSWconcentration 70%WSWconcentration 63%WNWconcentration 63%WNWconcentration 50%SWconcentration 93%SSWconcentration 96%SSWconcentration 99%
Mean water temperature(°C)10.310.410.410.310.310.310.310.310.310.310.210.210.210.210.210.310.110.110.110.110.110.110.210.210.19.99.99.99.9

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