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Sandown Bay wave buoy daily means for Sep 2021

Daily means from the Sandown 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

1,431 wave-buoy observations covered all 30 days. Typical wave height was 0.9 ft (10th–90th percentile 0.5–2.5 ft), while mean average of more than one wave period type was 5.2 seconds (10th–90th percentile 3.2–7.2 seconds). Mean water temperature was 18.5°C (10th–90th percentile 18.2–18.8°C). 9 of 5,698 checked values (0.2%) were excluded by quality control. Across 11 comparable years, mean wave height was below the same-month mean of 1.4 ft and mean wave period was the same as the same-month mean of 5.2 seconds.

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

Typical Significant Wave Height

0.9ft
Mean: 1.3 ft
P10–P90: 0.5 — 2.5 ft
Recorded extremes

0.3 — 7 ft

Mean Observed Wave Period

5.2secs
P10–P90: 3.2 — 7.2secs
Recorded extremes

1.7 — 18.2secs

Available for 717 of 718 hourly samples

Observed Wave Direction

SSE

Circular concentration: 86%

Mean Water Temperature

18.5°C
P10–P90: 18.2 — 18.8°C
Recorded extremes

17.7 — 19.2°C

Compared With Previous Septembers

Historical baseline from 15,808 observations across 11 years.

Wave Height
1.3ft
0.1ft below mean
Historical mean 1.444ft
Wave Period
5.2s
In line with the historical mean
Historical mean 5.2s
Water Temperature
18.5°C
0.6°C above mean
Historical mean 17.9°C

Chart showing grouped wave observations for Sandown 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 Sandown Bay wave buoy

Sandown Bay is a Channel Coastal Observatory National Network wave station off the east coast of the Isle of Wight. Its nearshore record represents conditions entering the bay between Culver Down and Dunnose, helping monitor a developed and erosion-sensitive frontage exposed to English Channel seas.

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.
Sandown Bay wave buoy daily means Sep 2021Last observation shown
Metric
Mean significant wave height (ft)222211121111221111111111114313
Mean maximum wave height (ft)343321131221321111111111125524
Mean peak period (s)45555444345655-744655554756665
Mean zero-crossing period (s)334433333343333333444333334444
Mean energy period (s)------------------------------
Mean wave power, kilowatts per metre------------------------------
Mean peak wave directionESEconcentration 100%ESEconcentration 99%ESEconcentration 99%ESEconcentration 99%SEconcentration 99%SEconcentration 96%SEconcentration 80%SEconcentration 97%SSEconcentration 95%Sconcentration 99%Sconcentration 100%SSEconcentration 97%ESEconcentration 93%SEconcentration 93%Sconcentration 97%Sconcentration 96%SSEconcentration 95%SSEconcentration 87%Sconcentration 95%SSEconcentration 81%SSEconcentration 93%Sconcentration 95%Sconcentration 98%Sconcentration 98%Sconcentration 96%Sconcentration 97%Sconcentration 99%Sconcentration 100%Sconcentration 94%Sconcentration 100%
Mean directional spread (°)15.315.719.321.626.630.731.926.933.327.423.432.023.326.841.729.328.830.828.430.930.230.627.126.033.529.421.120.125.420.7
Mean water temperature(°C)18.218.218.318.318.318.318.418.518.518.618.618.718.618.718.718.718.718.818.818.618.618.718.718.718.718.718.618.418.117.9

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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