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Porthleven wave buoy observations on Sun, Sep 20, 2020

Hourly readings from the Porthleven wave buoy for Sun, Sep 20, 2020, including available wave height, period, direction, wind and sea temperature data.

Last observation shown

Oldest observation available

Daily means for

Latest

Period Summary

Programmatically generated summary. Hog Says

48 wave-buoy observations were recorded during the day. Typical wave height was 1.6 ft (10th–90th percentile 1.4–2 ft), while mean peak wave period was 12.1 seconds (10th–90th percentile 10.8–13.7 seconds). Mean water temperature was 16.2°C (10th–90th percentile 15.9–16.4°C). All 192 checked values passed quality control.

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

Line chart showing wave height, wave period and sea temperature for Porthleven. Use the detailed observations table below for the same data in text form.

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; hours run left to right. Times use your device time zone.
Porthleven wave buoy hourly observations Sun, Sep 20, 2020Last observation shown
Metric
Significant wave height (ft)211222222222222222222222211111112222222222221121
Maximum wave height (ft)222333343433333333333322222222223322232233222222
Peak period (s)151514141413131313121312131312121212131211121313121112111312121311131112111111111111121110111111
Zero-crossing period (s)989888877666666666666666667676777666666666666665
Energy period (s)------------------------------------------------
Wave power, kilowatts per metre------------------------------------------------
Peak wave directionWSWSWWSWWSWWSWWSWWSWWSWWSWSWWSWWSWWSWWSWWSWWSWWSWWSWWSWSWSWSWWSWSWSWSWSWSWWSWWSWSWWSWWSWWSWWSWWSWWSWWSWWSWWSWWSWWSWSWWSWWSWWSWWSWWSW
Directional spread (°)51.059.042.029.029.031.043.059.044.035.036.040.034.033.028.019.020.017.039.040.029.032.059.036.045.030.050.041.033.038.040.054.041.035.023.034.044.031.029.025.031.030.025.032.031.046.035.059.0
Water temperature(°C)16.016.016.016.016.016.016.016.016.016.016.016.015.916.015.915.916.015.915.915.916.016.116.116.316.416.316.316.416.316.316.316.316.316.416.416.416.416.416.416.616.616.616.416.416.416.316.416.4

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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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