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Porthleven wave buoy monthly means for 2020

Monthly means from the Porthleven wave buoy for 2020, including available wave height, period, direction, wind and sea temperature data.

Last observation shown

Data available:  to 

Latest

Period Summary

Programmatically generated summary. Hog Says

17,244 wave-buoy observations covered 361 of 366 days (99%). Typical wave height was 3 ft (10th–90th percentile 1.2–9 ft), while mean average of more than one wave period type was 10.1 seconds (10th–90th percentile 6.1–13.9 seconds). Typical wind was 0 mph and mean water temperature was 12.6°C (10th–90th percentile 9.6–15.9°C). 245 of 69,795 checked values (0.4%) were excluded by quality control.

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

Typical Significant Wave Height

3ft
Mean: 4.3 ft
P10–P90: 1.2 — 9 ft
Recorded extremes

0.5 — 19 ft

Available for 8,623 of 8,625 hourly samples

Mean Observed Wave Period

10.1secs
P10–P90: 6.1 — 13.9secs
Recorded extremes

1.7 — 22.2secs

Available for 8,602 of 8,625 hourly samples

Observed Wave Direction

SW

Circular concentration: 96%

Mean Water Temperature

12.6°C
P10–P90: 9.6 — 15.9°C
Recorded extremes

9 — 19.2°C

Available for 8,624 of 8,625 hourly samples

Chart showing grouped wave observations for Porthleven. Use the table on this page for a text version of the same measurements. To open daily observations, use a linked month 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; months run left to right.
Porthleven wave buoy monthly means 2020Last observation shown
Metric
Mean significant wave height (ft)QC rejectedQC rejected4333332656
Mean maximum wave height (ft)9137444454889
Mean peak period (s)11111111119981091111
Mean zero-crossing period (s)666655555566
Mean energy period (s)------------
Mean reported period (s)11111111119989046
Mean wave power, kilowatts per metre------------
Mean peak wave directionSWconcentration 99%SWconcentration 99%SWconcentration 92%SWconcentration 95%SWconcentration 96%SWconcentration 95%SWconcentration 92%SWconcentration 97%WSWconcentration 94%SWconcentration 97%SWconcentration 97%SWconcentration 98%
Mean directional spread (°)23.520.128.036.332.328.329.425.128.922.423.521.6
Mean reported wave directionSWconcentration 98%SWconcentration 99%SWconcentration 91%SWconcentration 94%SWconcentration 95%SWconcentration 94%SWconcentration 92%SWconcentration 97%WSWconcentration 99%SWconcentration 98%SWconcentration 97%SWconcentration 98%
Mean water temperature(°C)10.19.79.510.712.514.614.616.415.914.212.711.1

Swipe sideways to see more months.

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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