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K4 wave buoy daily means for Sep 2012

Daily means from the K4 wave buoy for Sep 2012, 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

633 wave-buoy observations covered all 30 days. Typical wave height was 10.5 ft (10th–90th percentile 6.2–16.7 ft), while mean reported wave period; measurement type unavailable was 7 seconds (10th–90th percentile 6–8 seconds). Typical wind was 20.7 mph (10th–90th percentile 11.5–29.9 mph) and mean water temperature was 14.1°C (10th–90th percentile 13.3–14.9°C). 1 of 3,165 checked values (0%) were excluded by quality control. Across 2 comparable years, mean wave height was above the same-month mean of 10.3 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

10.5ft
Mean: 10.9 ft
P10–P90: 6.2 — 16.7 ft
Recorded extremes

4.3 — 22 ft

Available for 632 of 633 hourly samples

Mean Wave Period

7secs
P10–P90: 6 — 8secs
Recorded extremes

5 — 10secs

Mean Water Temperature

14.1°C
P10–P90: 13.3 — 14.9°C
Recorded extremes

13 — 15.1°C

Typical Wind

WSW, 20.7mph
Mean: 20.5 mph
P10–P90: 11.5 — 29.9 mph
Recorded extremes

4.6 — 42.6 mph

Circular concentration: 62%

Compared With Previous Septembers

Historical baseline from 1,437 observations across 2 years.

Wave Height
10.9ft
0.6ft above mean
Historical mean 10.3ft
Wave Period
7s
0.2s below mean
Historical mean 7.2s
Water Temperature
14.1°C
0.6°C above mean
Historical mean 13.5°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 Sep 2012Last observation shown
Metric
Mean wave height (ft)1281015121177109141014QC rejected1312131178661081615QC rejected15QC rejected15
Mean observed period(s)7Reported7Reported6Reported9Reported9Reported7Reported6Reported6Reported7Reported7Reported8Reported7Reported7Reported9Reported8Reported7Reported8Reported7Reported7Reported6Reported6Reported6Reported9Reported8Reported7Reported8Reported6Reported8Reported7Reported8Reported
Mean wave power(kW/m)------------------------------
Mean wind directionSWconcentration 87%WSWconcentration 98%SWconcentration 84%Wconcentration 99%WSWconcentration 78%SWconcentration 95%WSWconcentration 95%Sconcentration 97%Sconcentration 90%WNWconcentration 94%WNWconcentration 90%WSWconcentration 95%WSWconcentration 96%Wconcentration 98%WSWconcentration 98%Wconcentration 98%WNWconcentration 94%NWconcentration 95%WSWconcentration 84%Variableconcentration 1%ENEconcentration 67%Sconcentration 95%SWconcentration 85%NNWconcentration 90%Nconcentration 98%Nconcentration 98%Wconcentration 90%WNWconcentration 98%SWconcentration 94%WSWconcentration 99%
Mean wind speed (mph)23172621152416181816231729252123242012181119129332619282527
Mean water temperature(°C)14.314.414.614.414.314.514.815.115.115.014.514.714.714.514.414.414.113.813.813.713.713.713.713.613.413.313.213.313.313.2

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 UK Met Office.

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