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Porthleven wave buoy daily means for Aug 2023

Daily means from the Porthleven wave buoy for Aug 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

1,489 wave-buoy observations covered all 31 days. Typical wave height was 2.4 ft (10th–90th percentile 1.3–6.1 ft), while mean average of more than one wave period type was 9.4 seconds (10th–90th percentile 5.6–15.4 seconds). Mean water temperature was 15.7°C (10th–90th percentile 14.7–16.9°C). 37 of 5,948 checked values (0.6%) were excluded by quality control. Across 10 comparable years, mean wave height was above the same-month mean of 2.8 ft and mean wave period was above the same-month mean of 7.7 seconds.

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

Typical Significant Wave Height

2.4ft
Mean: 3.2 ft
P10–P90: 1.3 — 6.1 ft
Recorded extremes

0.8 — 12.4 ft

Mean Observed Wave Period

9.4secs
P10–P90: 5.6 — 15.4secs
Recorded extremes

2.9 — 20secs

Available for 741 of 744 hourly samples

Observed Wave Direction

SW

Circular concentration: 94%

Mean Water Temperature

15.7°C
P10–P90: 14.7 — 16.9°C
Recorded extremes

13.9 — 21.8°C

Compared With Previous Augusts

Historical baseline from 7,334 observations across 10 years.

Wave Height
3.2ft
0.4ft above mean
Historical mean 2.8ft
Wave Period
9.4s
1.7s above mean
Historical mean 7.7s
Water Temperature
15.7°C
0.5°C below mean
Historical mean 16.2°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 2023Last observation shown
Metric
Mean significant wave height (ft)4953632322465522149432112222223
Mean maximum wave height (ft)714849534325878422613754213333334
Mean peak period (s)710111099967681210713161710109109111586671487
Mean zero-crossing period (s)5665555444555556657655543434444
Mean energy period (s)-------------------------------
Mean reported period (s)5665554444555556557655543434444
Mean wave power, kilowatts per metre-------------------------------
Mean peak wave directionSWconcentration 99%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%WSWconcentration 99%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%SWconcentration 97%SWconcentration 98%WSWconcentration 100%WSWconcentration 98%SWconcentration 100%SWconcentration 97%SSWconcentration 93%Sconcentration 90%SSWconcentration 95%SWconcentration 100%SWconcentration 100%WSWconcentration 100%WSWconcentration 98%SWconcentration 89%SSWconcentration 89%SWconcentration 96%WSWconcentration 100%WSWconcentration 100%WSWconcentration 98%SWconcentration 92%WSWconcentration 97%SWconcentration 95%
Mean directional spread (°)20.918.418.324.119.319.627.120.825.127.218.216.617.619.742.857.863.635.419.918.920.525.142.567.334.424.424.627.848.426.028.6
Mean reported wave directionSWconcentration 99%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%WSWconcentration 99%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%SWconcentration 97%SWconcentration 98%WSWconcentration 100%WSWconcentration 98%SWconcentration 99%SWconcentration 98%SSWconcentration 89%Sconcentration 90%SSWconcentration 96%SWconcentration 100%SWconcentration 100%WSWconcentration 100%WSWconcentration 99%SWconcentration 90%SSWconcentration 90%SWconcentration 95%WSWconcentration 100%WSWconcentration 100%WSWconcentration 98%SWconcentration 91%SWconcentration 93%SWconcentration 96%
Mean water temperature(°C)15.515.315.014.514.414.714.714.915.815.415.315.616.016.116.615.915.515.415.516.717.117.517.116.015.816.015.815.916.016.016.0

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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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