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K4 wave buoy daily means for Apr 2020

Daily means from the K4 wave buoy for Apr 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

711 wave-buoy observations covered all 30 days. Typical wave height was 6.9 ft (10th–90th percentile 5.2–13.5 ft), while mean reported wave period; measurement type unavailable was 6.8 seconds (10th–90th percentile 5–8 seconds). Typical wind was 0 mph (10th–90th percentile 0–26.4 mph) and mean water temperature was 10.2°C (10th–90th percentile 9.8–10.8°C). 6 of 3,555 checked values (0.2%) were excluded by quality control. Across 8 comparable years, mean wave height was below the same-month mean of 10 ft and mean wave period was below the same-month mean of 7.2 seconds.

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

Typical Wave Height

6.9ft
Mean: 8.2 ft
P10–P90: 5.2 — 13.5 ft
Recorded extremes

3.3 — 19.4 ft

Available for 709 of 711 hourly samples

Mean Wave Period

6.8secs
P10–P90: 5 — 8secs
Recorded extremes

5 — 11secs

Available for 710 of 711 hourly samples

Mean Water Temperature

10.2°C
P10–P90: 9.8 — 10.8°C
Recorded extremes

9.6 — 11.2°C

Typical Wind

N, 0mph
Mean: 7.6 mph
P10–P90: 0 — 26.4 mph
Recorded extremes

0 — 36.9 mph

Circular concentration: 34%

Available for 708 of 711 hourly samples

Compared With Previous Aprils

Historical baseline from 5,080 observations across 8 years.

Wave Height
8.2ft
1.8ft below mean
Historical mean 10ft
Wave Period
6.8s
0.4s below mean
Historical mean 7.2s
Water Temperature
10.2°C
0.3°C below mean
Historical mean 10.5°C

Chart showing grouped wave observations for K4. 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 K4 wave buoy

K4 (WMO 62105) is a UK Met Office buoy in the North Atlantic northwest of Ireland. Its remote position samples weather and sea conditions moving towards northern UK and Irish waters. The international station feed can include wind, pressure, temperature and wave observations, although the reported parameters vary with sensor availability.

Metrics are rows; days run left to right.
K4 wave buoy daily means Apr 2020Last observation shown
Metric
Mean wave height (ft)813111016171412866QC rejectedQC rejected66875478576656677
Mean observed period(s)6Reported7Reported8Reported6Reported8Reported8Reported7Reported8Reported7Reported7Reported5Reported8Reported8Reported7Reported7Reported8Reported6Reported5Reported5Reported7Reported7Reported6Reported9Reported7Reported8Reported6Reported6Reported6Reported6Reported6Reported
Mean wave power(kW/m)------------------------------
Mean wind directionNNWconcentration 81%WNWconcentration 90%Wconcentration 91%Sconcentration 85%SSEconcentration 96%WSWconcentration 96%SSWconcentration 98%Variableconcentration 23%SEconcentration 93%SEconcentration 100%SEconcentration 100%SEconcentration 100%SEconcentration 100%Econcentration 39%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%Nconcentration 100%
Mean wind speed (mph)112316253327281510101010106----------------
Mean water temperature(°C)9.89.89.89.89.89.79.89.910.010.09.910.09.910.010.110.110.010.010.310.210.210.510.710.710.710.910.911.010.710.4

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 UK Met Office.

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