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Penzance wave buoy daily means for Jul 2020

Daily means from the Penzance wave buoy for Jul 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

742 wave-buoy observations covered all 31 days. Typical wave height was 1 ft (10th–90th percentile 0.5–2.2 ft), while mean reported wave period; measurement type unavailable was 7.5 seconds (10th–90th percentile 3–14 seconds). Mean water temperature was 14.6°C (10th–90th percentile 13.8–15.6°C). 20 of 2,968 checked values (0.7%) were excluded by quality control. Across 9 comparable years, mean wave height was the same as the same-month mean of 1.2 ft and mean wave period was the same as the same-month mean of 7.5 seconds.

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

Typical Significant Wave Height

1ft
Mean: 1.2 ft
P10–P90: 0.5 — 2.2 ft
Recorded extremes

0.3 — 6.8 ft

Mean Observed Wave Period

7.5secs
P10–P90: 3 — 14secs
Recorded extremes

2 — 20secs

Available for 722 of 742 hourly samples

Observed Wave Direction

S

Circular concentration: 91%

Mean Water Temperature

14.6°C
P10–P90: 13.8 — 15.6°C
Recorded extremes

13.4 — 16.8°C

Compared With Previous Julys

Historical baseline from 6,619 observations across 9 years.

Wave Height
1.2ft
0ft above mean
Historical mean 1.2ft
Wave Period
7.5s
In line with the historical mean
Historical mean 7.5s
Water Temperature
14.6°C
1°C below mean
Historical mean 15.6°C

Chart showing grouped wave observations for Penzance. 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 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; days run left to right.
Penzance wave buoy daily means Jul 2020Last observation shown
Metric
Mean significant wave height (ft)21232111211111111111001122QC rejected1122
Mean observed period(s)5Reported6Reported6Reported7Reported7Reported11Reported10Reported5Reported5Reported8ReportedQC rejected11Reported5Reported5Reported6Reported7Reported9Reported6Reported4Reported11Reported13Reported13Reported15Reported12Reported5Reported6Reported7Reported7Reported7Reported4Reported6Reported
Mean wave power, kilowatts per metre-------------------------------
Mean wave directionSSWconcentration 100%Sconcentration 95%SSWconcentration 100%SSWconcentration 100%SSWconcentration 100%Sconcentration 100%SSWconcentration 92%SSWconcentration 96%Sconcentration 100%Sconcentration 83%Sconcentration 98%Sconcentration 98%Sconcentration 96%SSWconcentration 59%Sconcentration 86%Sconcentration 99%Sconcentration 99%Sconcentration 98%Variableconcentration 12%SSEconcentration 96%Sconcentration 98%Sconcentration 97%Sconcentration 98%Sconcentration 99%Sconcentration 99%Sconcentration 100%SSWconcentration 100%Sconcentration 100%Sconcentration 100%SSEconcentration 96%Sconcentration 92%
Mean water temperature(°C)14.214.014.014.014.013.713.813.914.114.114.715.215.214.214.013.814.214.314.514.414.715.415.315.114.914.714.814.915.415.816.2

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.

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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