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K4 wave buoy daily means for Sep 2017

Daily means from the K4 wave buoy for Sep 2017, 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

675 wave-buoy observations covered all 30 days. Typical wave height was 9.8 ft (10th–90th percentile 5.6–17.1 ft), while mean reported wave period; measurement type unavailable was 7 seconds (10th–90th percentile 6–8 seconds). Typical wind was 18.3 mph (10th–90th percentile 5.8–30 mph) and mean water temperature was 13.9°C (10th–90th percentile 13.3–14.8°C). 61 of 3,374 checked values (1.8%) were excluded by quality control. Across 7 comparable years, mean wave height was above the same-month mean of 9.7 ft and mean wave period was above the same-month mean of 6.9 seconds.

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

Typical Wave Height

9.8ft
Mean: 10.6 ft
P10–P90: 5.6 — 17.1 ft
Recorded extremes

0 — 30.2 ft

Available for 658 of 675 hourly samples

Mean Wave Period

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

5 — 11secs

Available for 657 of 675 hourly samples

Mean Water Temperature

13.9°C
P10–P90: 13.3 — 14.8°C
Recorded extremes

13.1 — 17°C

Available for 671 of 675 hourly samples

Typical Wind

WSW, 18.3mph
Mean: 18.2 mph
P10–P90: 5.8 — 30 mph
Recorded extremes

0 — 51.9 mph

Circular concentration: 37%

Available for 652 of 675 hourly samples

Compared With Previous Septembers

Historical baseline from 4,758 observations across 7 years.

Wave Height
10.6ft
0.9ft above mean
Historical mean 9.7ft
Wave Period
7s
0.1s above mean
Historical mean 6.9s
Water Temperature
13.9°C
0.1°C below mean
Historical mean 14°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 2017Last observation shown
Metric
Mean wave height (ft)58710131310121217189101210865676714159141212QC rejected13
Mean observed period(s)6Reported6Reported7Reported7Reported8Reported8Reported6Reported7Reported7Reported8Reported9Reported7Reported7Reported7Reported7Reported7Reported7Reported6Reported5Reported6Reported6Reported6Reported8Reported9Reported7Reported7Reported8Reported7Reported9Reported8Reported
Mean wave power(kW/m)------------------------------
Mean wind directionSWconcentration 60%SSEconcentration 62%SWconcentration 72%SWconcentration 81%Wconcentration 86%Wconcentration 79%Wconcentration 74%NWconcentration 91%NWconcentration 89%Wconcentration 80%NWconcentration 94%Wconcentration 82%NWconcentration 88%NNWconcentration 98%NNWconcentration 92%NNWconcentration 96%ESEconcentration 84%Sconcentration 73%Sconcentration 61%WSWconcentration 72%SWconcentration 60%SSWconcentration 68%SSEconcentration 43%SSWconcentration 83%SSEconcentration 90%SEconcentration 42%WSWconcentration 60%SSEconcentration 53%WSWconcentration 66%Wconcentration 61%
Mean wind speed (mph)112013242416192624302312181914121213181113133213212413252715
Mean water temperature(°C)14.914.814.814.814.814.714.614.614.514.113.913.613.513.413.313.413.513.713.713.713.613.613.713.713.613.613.713.313.313.1

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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