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Porthleven wave buoy daily means for Aug 2020

Daily means from the Porthleven wave buoy for Aug 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

1,486 wave-buoy observations covered all 31 days. Typical wave height was 2.2 ft (10th–90th percentile 1–7.4 ft), while mean average of more than one wave period type was 8.2 seconds (10th–90th percentile 5.1–10.6 seconds). Mean water temperature was 16.4°C (10th–90th percentile 14.9–17.6°C). 12 of 5,908 checked values (0.2%) were excluded by quality control. Across 7 comparable years, mean wave height was above the same-month mean of 2.9 ft and mean wave period was below the same-month mean of 8.6 seconds.

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

Typical Significant Wave Height

2.2ft
Mean: 3.3 ft
P10–P90: 1 — 7.4 ft
Recorded extremes

0.6 — 16.9 ft

Mean Observed Wave Period

8.2secs
P10–P90: 5.1 — 10.6secs
Recorded extremes

1.8 — 16.7secs

Available for 741 of 743 hourly samples

Observed Wave Direction

SW

Circular concentration: 97%

Mean Water Temperature

16.4°C
P10–P90: 14.9 — 17.6°C
Recorded extremes

13.9 — 19.2°C

Compared With Previous Augusts

Historical baseline from 5,144 observations across 7 years.

Wave Height
3.3ft
0.4ft above mean
Historical mean 2.92ft
Wave Period
8.2s
0.4s below mean
Historical mean 8.6s
Water Temperature
16.4°C
0.4°C above mean
Historical mean 16°C

Chart showing grouped wave observations for Porthleven. 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 Porthleven wave buoy

Porthleven is a National Network Datawell Directional WaveRider off Cornwall's exposed south coast. First deployed in October 2011, it characterises waves approaching the Porthleven frontage from the western English Channel, where Atlantic swell can wrap around Land's End and meet locally generated seas.

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.
Porthleven wave buoy daily means Aug 2020Last observation shown
Metric
Mean significant wave height (ft)43235322211112112261112643QC rejected545211
Mean maximum wave height (ft)6535853332222321249171896415867311
Mean peak period (s)10987710109910128107766571112108691078986
Mean zero-crossing period (s)5555555544445445445775546656454
Mean energy period (s)-------------------------------
Mean reported period (s)1098771010991011997766571012108691078986
Mean wave power, kilowatts per metre-------------------------------
Mean peak wave directionWSWconcentration 100%WSWconcentration 100%WSWconcentration 100%SWconcentration 99%SWconcentration 99%WSWconcentration 99%WSWconcentration 99%WSWconcentration 100%WSWconcentration 100%WSWconcentration 97%SWconcentration 93%WSWconcentration 100%WSWconcentration 100%WSWconcentration 99%SWconcentration 100%SWconcentration 100%SWconcentration 98%SWconcentration 100%SSWconcentration 99%SWconcentration 100%SWconcentration 100%WSWconcentration 99%WSWconcentration 100%SWconcentration 99%SWconcentration 96%WSWconcentration 100%SWconcentration 96%WSWconcentration 99%WSWconcentration 100%WSWconcentration 100%SWconcentration 95%
Mean directional spread (°)16.718.827.024.119.320.424.927.733.042.250.433.421.521.829.030.528.124.018.118.817.719.319.023.418.315.420.019.030.036.635.1
Mean reported wave directionWSWconcentration 100%WSWconcentration 100%WSWconcentration 100%SWconcentration 99%SWconcentration 98%WSWconcentration 99%WSWconcentration 99%WSWconcentration 99%WSWconcentration 97%WSWconcentration 92%WSWconcentration 94%WSWconcentration 98%WSWconcentration 100%WSWconcentration 99%SWconcentration 99%SWconcentration 99%SWconcentration 97%SWconcentration 100%SSWconcentration 99%SWconcentration 100%SWconcentration 100%WSWconcentration 99%WSWconcentration 100%SWconcentration 99%SWconcentration 96%WSWconcentration 100%SWconcentration 96%WSWconcentration 99%WSWconcentration 99%WSWconcentration 99%SWconcentration 94%
Mean water temperature(°C)15.715.615.515.415.615.616.315.615.015.015.816.217.217.918.317.417.217.517.417.217.317.417.317.116.916.816.816.114.814.714.9

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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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