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Bracklesham Bay wave buoy daily means for Sep 2021

Daily means from the Bracklesham Bay wave buoy for Sep 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

1,439 wave-buoy observations covered all 30 days. Typical wave height was 1.1 ft (10th–90th percentile 0.7–3.4 ft), while mean average of more than one wave period type was 6.6 seconds (10th–90th percentile 3–12.2 seconds). Mean water temperature was 18.5°C (10th–90th percentile 17.9–18.9°C). 20 of 5,701 checked values (0.4%) were excluded by quality control. Across 11 comparable years, mean wave height was below the same-month mean of 2.1 ft and mean wave period was below the same-month mean of 6.7 seconds.

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

Typical Significant Wave Height

1.1ft
Mean: 1.6 ft
P10–P90: 0.7 — 3.4 ft
Recorded extremes

0.4 — 8 ft

Mean Observed Wave Period

6.6secs
P10–P90: 3 — 12.2secs
Recorded extremes

1.7 — 20secs

Available for 719 of 720 hourly samples

Observed Wave Direction

SSW

Circular concentration: 87%

Mean Water Temperature

18.5°C
P10–P90: 17.9 — 18.9°C
Recorded extremes

16.1 — 19.4°C

Compared With Previous Septembers

Historical baseline from 15,603 observations across 11 years.

Wave Height
1.6ft
0.5ft below mean
Historical mean 2.133ft
Wave Period
6.6s
0.1s below mean
Historical mean 6.7s
Water Temperature
18.5°C
1°C above mean
Historical mean 17.5°C

Chart showing grouped wave observations for Bracklesham Bay. 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 Bracklesham Bay wave buoy

Bracklesham Bay is a Channel Coastal Observatory National Network wave station off the West Sussex coast. Its nearshore position records conditions entering the broad bay between Selsey and Hayling Island, supporting coastal management along an exposed beach frontage west of Chichester Harbour.

Its current data source reports wave height, wave period, wave direction, directional spread, wave power and sea temperature.

Metrics are rows; days run left to right.
Bracklesham Bay wave buoy daily means Sep 2021Last observation shown
Metric
Mean significant wave height (ft)111111111221111111111122125535
Mean maximum wave height (ft)121111121341222212221133128858
Mean peak period (s)4444468434597151410789686451166667
Mean zero-crossing period (s)333333333334344434434433434444
Mean energy period (s)------------------------------
Mean wave power, kilowatts per metre------------------------------
Mean peak wave directionSEconcentration 77%SEconcentration 79%SSEconcentration 98%SSEconcentration 97%Sconcentration 96%SSWconcentration 97%Sconcentration 91%Sconcentration 95%SSWconcentration 96%SWconcentration 99%SWconcentration 100%SSWconcentration 96%SSEconcentration 92%SSWconcentration 94%SSWconcentration 99%SSWconcentration 98%SSWconcentration 98%SSWconcentration 99%SSWconcentration 99%SWconcentration 94%SSWconcentration 99%SWconcentration 97%WSWconcentration 90%SWconcentration 99%SSWconcentration 99%SWconcentration 98%SSWconcentration 99%SSWconcentration 100%SWconcentration 92%SWconcentration 100%
Mean directional spread (°)26.524.826.027.028.929.831.127.432.525.321.030.828.334.329.125.325.024.824.225.324.126.724.624.227.525.219.520.020.619.5
Mean water temperature(°C)18.118.018.118.218.318.618.818.919.019.018.918.818.718.618.718.818.818.818.818.618.618.618.518.518.618.618.417.917.316.9

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.

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.

Learn how SurfHog combines, checks and summarizes observations in the data and methodology notes.

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