Skip to content
Surfhog home
Menu

Porthleven wave buoy daily means for Mar 2020

Daily means from the Porthleven wave buoy for Mar 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 4.2 ft (10th–90th percentile 1.2–8.1 ft), while mean average of more than one wave period type was 10.7 seconds (10th–90th percentile 6.7–13.8 seconds). Mean water temperature was 9.5°C (10th–90th percentile 9.2–9.8°C). 18 of 5,881 checked values (0.3%) were excluded by quality control. Across 7 comparable years, mean wave height was below the same-month mean of 4.5 ft and mean wave period was below the same-month mean of 11.3 seconds.

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

Typical Significant Wave Height

4.2ft
Mean: 4.4 ft
P10–P90: 1.2 — 8.1 ft
Recorded extremes

0.5 — 12.8 ft

Mean Observed Wave Period

10.7secs
P10–P90: 6.7 — 13.8secs
Recorded extremes

1.7 — 20secs

Available for 742 of 743 hourly samples

Observed Wave Direction

SW

Circular concentration: 92%

Mean Water Temperature

9.5°C
P10–P90: 9.2 — 9.8°C
Recorded extremes

9 — 10.1°C

Compared With Previous Marchs

Historical baseline from 4,993 observations across 7 years.

Wave Height
4.4ft
0.1ft below mean
Historical mean 4.528ft
Wave Period
10.7s
0.6s below mean
Historical mean 11.3s
Water Temperature
9.5°C
0.1°C above mean
Historical mean 9.4°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 Mar 2020Last observation shown
Metric
Mean significant wave height (ft)86553561088796664553232233221111
Mean maximum wave height (ft)1310885910151313111391096774342344432221
Mean peak period (s)111011910111011121010121210912111213126101117131212121198
Mean zero-crossing period (s)6665565666666566556535577766454
Mean energy period (s)-------------------------------
Mean reported period (s)111012101011111112109111210912111213117111117131213121188
Mean wave power, kilowatts per metre-------------------------------
Mean peak wave directionSWconcentration 100%SWconcentration 99%WSWconcentration 100%SWconcentration 100%SWconcentration 100%WSWconcentration 99%SWconcentration 99%WSWconcentration 100%WSWconcentration 99%WSWconcentration 99%SWconcentration 99%WSWconcentration 100%WSWconcentration 100%SWconcentration 99%SWconcentration 97%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%WSWconcentration 99%SWconcentration 93%SSEconcentration 84%SWconcentration 90%WSWconcentration 99%WSWconcentration 96%WSWconcentration 100%WSWconcentration 99%WSWconcentration 99%WSWconcentration 83%SWconcentration 86%SSWconcentration 96%SSEconcentration 70%
Mean directional spread (°)17.920.518.619.621.419.118.716.520.017.419.918.721.418.419.220.315.921.536.749.425.736.339.150.338.334.940.751.144.940.240.5
Mean reported wave directionSWconcentration 100%SWconcentration 99%WSWconcentration 100%SWconcentration 100%SWconcentration 99%WSWconcentration 99%SWconcentration 99%WSWconcentration 100%WSWconcentration 99%WSWconcentration 99%SWconcentration 99%WSWconcentration 100%WSWconcentration 99%WSWconcentration 99%SWconcentration 97%WSWconcentration 100%WSWconcentration 100%WSWconcentration 100%WSWconcentration 99%SWconcentration 77%SSEconcentration 77%SWconcentration 90%SWconcentration 94%WSWconcentration 95%WSWconcentration 99%WSWconcentration 99%WSWconcentration 99%WSWconcentration 82%SWconcentration 81%SSWconcentration 93%Sconcentration 64%
Mean water temperature(°C)9.39.29.29.29.29.29.39.49.49.59.79.69.69.69.69.59.69.99.89.79.69.59.59.79.89.89.89.89.79.69.5

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