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Penzance wave buoy monthly means for 2021

Monthly means from the Penzance wave buoy for 2021, 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

8,376 wave-buoy observations covered 363 of 365 days (99%). Typical wave height was 1.5 ft (10th–90th percentile 0.6–4.5 ft), while mean reported wave period; measurement type unavailable was 4.3 seconds (10th–90th percentile 3–6 seconds). Typical wind was 0 mph and mean water temperature was 12.9°C (10th–90th percentile 9.4–16.8°C). All 41,880 checked values passed quality control.

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

Typical Significant Wave Height

1.5ft
Mean: 2.1 ft
P10–P90: 0.6 — 4.5 ft
Recorded extremes

0.3 — 11.5 ft

Mean Observed Wave Period

4.3secs
P10–P90: 3 — 6secs
Recorded extremes

2 — 8secs

Observed Wave Direction

S

Circular concentration: 91%

Mean Water Temperature

12.9°C
P10–P90: 9.4 — 16.8°C
Recorded extremes

7.1 — 21.5°C

Chart showing grouped wave observations for Penzance. 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 Penzance wave buoy

Penzance is a Datawell Directional WaveRider station in Mount's Bay off west Cornwall. First deployed by the National Network in April 2007, it records the comparatively sheltered wave climate on the bay's western side. Available observations include wave height, period and direction, sea temperature and calculated wave power.

Metrics are rows; months run left to right.
Penzance wave buoy monthly means 2021Last observation shown
Metric
Mean significant wave height (ft)252131111313
Mean observed period(s)5Reported5Reported4Reported4Reported4Reported4Reported4Reported4Reported4Reported5Reported4Reported4Reported
Mean wave power, kilowatts per metre------------
Mean wave directionSconcentration 90%Sconcentration 96%Sconcentration 96%SSEconcentration 75%Sconcentration 97%Sconcentration 92%Sconcentration 94%Sconcentration 95%Sconcentration 96%Sconcentration 99%Sconcentration 76%Sconcentration 91%
Mean water temperature(°C)9.59.19.710.511.714.816.515.717.214.913.311.7

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.

Which wave period is shown?

The table shows the best period measurement supplied for each observation. It is not necessarily the energy period used to calculate wave power.

Tp
Peak period: the period at the strongest spectral peak.
Tavg
The provider's average wave period.
Tm02
A mean period calculated from the wave spectrum.
Tz
Mean zero-crossing period.
Reported
A legacy value whose period type was not recorded.
Mixed
A daily or monthly mean containing more than one period type.

Wave power needs a genuine energy period (Te). SurfHog does not substitute Tp, Tavg, Tm02 or Tz when Te is missing.

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.

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