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Bracklesham Bay wave buoy daily means for Sep 2020

Daily means from the Bracklesham Bay wave buoy for Sep 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

1,440 wave-buoy observations covered all 30 days. Typical wave height was 1.6 ft (10th–90th percentile 0.7–3.7 ft), while mean average of more than one wave period type was 6.3 seconds (10th–90th percentile 3.1–11.5 seconds). Mean water temperature was 18°C (10th–90th percentile 16.2–18.8°C). 19 of 5,699 checked values (0.3%) were excluded by quality control. Across 10 comparable years, mean wave height was below the same-month mean of 2.2 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

1.6ft
Mean: 1.8 ft
P10–P90: 0.7 — 3.7 ft
Recorded extremes

0.3 — 7.3 ft

Mean Observed Wave Period

6.3secs
P10–P90: 3.1 — 11.5secs
Recorded extremes

1.7 — 25secs

Available for 717 of 720 hourly samples

Observed Wave Direction

SSW

Circular concentration: 87%

Mean Water Temperature

18°C
P10–P90: 16.2 — 18.8°C
Recorded extremes

14.7 — 19.4°C

Compared With Previous Septembers

Historical baseline from 14,164 observations across 10 years.

Wave Height
1.8ft
0.4ft below mean
Historical mean 2.165ft
Wave Period
6.3s
0.4s below mean
Historical mean 6.7s
Water Temperature
18°C
0.5°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 2020Last observation shown
Metric
Mean significant wave height (ft)114222221112111121211135432224
Mean maximum wave height (ft)126332232123211122322258643226
Mean peak period (s)575656655454576855-9545791010965
Mean zero-crossing period (s)344333433333333333434345533334
Mean energy period (s)------------------------------
Mean wave power, kilowatts per metre------------------------------
Mean peak wave directionSconcentration 92%SSWconcentration 99%SWconcentration 99%SWconcentration 96%SWconcentration 85%SWconcentration 99%SWconcentration 99%SWconcentration 100%SWconcentration 99%SSEconcentration 80%SWconcentration 92%SWconcentration 99%SWconcentration 99%Sconcentration 93%Sconcentration 95%SWconcentration 92%SSEconcentration 91%SSEconcentration 75%SSWconcentration 97%SSWconcentration 75%Sconcentration 95%SWconcentration 96%SWconcentration 100%SSWconcentration 100%SWconcentration 89%SWconcentration 87%SWconcentration 75%SWconcentration 80%SWconcentration 99%SSWconcentration 100%
Mean directional spread (°)31.624.519.723.523.224.020.719.620.929.624.019.423.926.128.432.427.228.938.231.727.426.220.419.118.124.926.623.322.821.9
Mean water temperature(°C)18.218.318.318.318.318.318.318.518.818.818.618.518.518.618.819.018.718.418.218.118.218.218.217.516.816.315.915.916.216.2

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.

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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