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K7 wave buoy daily means for Apr 2021

Daily means from the K7 wave buoy for Apr 2021, 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

719 wave-buoy observations covered all 30 days. Typical wave height was 7.2 ft (10th–90th percentile 3.9–19.4 ft), while mean reported wave period; measurement type unavailable was 8.1 seconds (10th–90th percentile 6–10 seconds). Typical wind was 17.2 mph (10th–90th percentile 9.2–32.4 mph). 2 of 2,876 checked values (0.1%) were excluded by quality control. Across 8 comparable years, mean wave height was above the same-month mean of 9.3 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 Wave Height

7.2ft
Mean: 9.6 ft
P10–P90: 3.9 — 19.4 ft
Recorded extremes

2.6 — 34.8 ft

Available for 717 of 719 hourly samples

Mean Wave Period

8.1secs
P10–P90: 6 — 10secs
Recorded extremes

5 — 13secs

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 719 hourly samples

Typical Wind

NW, 17.2mph
Mean: 19.1 mph
P10–P90: 9.2 — 32.4 mph
Recorded extremes

1.1 — 46.1 mph

Circular concentration: 34%

Compared With Previous Aprils

Historical baseline from 5,524 observations across 8 years.

Wave Height
9.6ft
0.3ft above mean
Historical mean 9.3ft
Wave Period
8.1s
0.4s above mean
Historical mean 7.7s
Water Temperature
–
Not enough comparable data
Historical mean 9.1°C

Chart showing grouped wave observations for K7. 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 K7 wave buoy

K7 (WMO 64046) is a UK Met Office buoy west of Shetland in the North Atlantic. Its position monitors ocean weather and sea conditions approaching the Northern Isles. The international feed can include wind, pressure, air and sea temperature, and wave observations when the relevant sensors are reporting.

Metrics are rows; days run left to right.
K7 wave buoy daily means Apr 2021Last observation shown
Metric
Mean wave height (ft)567152732201517149974498QC rejected1088655455465
Mean observed period(s)7Reported7Reported7Reported8Reported11Reported12Reported11Reported9Reported9Reported9Reported9Reported10Reported9Reported8Reported7Reported8Reported8Reported9Reported9Reported7Reported8Reported8Reported8Reported8Reported9Reported7Reported6Reported6Reported6Reported6Reported
Mean wave power(kW/m)------------------------------
Mean wind directionWNWconcentration 89%NNWconcentration 91%Wconcentration 98%NWconcentration 82%NNWconcentration 99%NNWconcentration 99%NWconcentration 67%WNWconcentration 63%NNWconcentration 96%NNWconcentration 95%Nconcentration 93%NNEconcentration 78%NWconcentration 69%Wconcentration 92%Sconcentration 97%Sconcentration 96%Sconcentration 96%SSWconcentration 91%Sconcentration 98%WNWconcentration 91%WNWconcentration 90%WNWconcentration 95%WSWconcentration 70%Variableconcentration 16%Sconcentration 97%SEconcentration 69%NEconcentration 95%NNEconcentration 93%NNEconcentration 96%Nconcentration 95%
Mean wind speed (mph)1817253538352030272112131212182219212022151267121916152014
Mean water temperature(°C)------------------------------

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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.

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 UK Met Office.

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