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Sandown Bay wave buoy daily means for Apr 2021

Daily means from the Sandown Bay wave buoy for Apr 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

1,433 wave-buoy observations covered all 30 days. Typical wave height was 1 ft (10th–90th percentile 0.4–3.1 ft), while mean average of more than one wave period type was 4.8 seconds (10th–90th percentile 3.2–6 seconds). Mean water temperature was 9.2°C (10th–90th percentile 8.7–10.2°C). 5 of 5,703 checked values (0.1%) were excluded by quality control. Across 11 comparable years, mean wave height was the same as the same-month mean of 1.4 ft and mean wave period was below the same-month mean of 5.9 seconds.

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

Typical Significant Wave Height

1ft
Mean: 1.4 ft
P10–P90: 0.4 — 3.1 ft
Recorded extremes

0.2 — 5.4 ft

Mean Observed Wave Period

4.8secs
P10–P90: 3.2 — 6secs
Recorded extremes

1.7 — 13.3secs

Observed Wave Direction

SE

Circular concentration: 89%

Mean Water Temperature

9.2°C
P10–P90: 8.7 — 10.2°C
Recorded extremes

8.5 — 10.7°C

Available for 718 of 719 hourly samples

Compared With Previous Aprils

Historical baseline from 15,828 observations across 11 years.

Wave Height
1.4ft
0ft below mean
Historical mean 1.444ft
Wave Period
4.8s
1.1s below mean
Historical mean 5.9s
Water Temperature
9.2°C
0.4°C below mean
Historical mean 9.6°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 Apr 2021Last observation shown
Metric
Mean significant wave height (ft)132111111111112211011333431111
Mean maximum wave height (ft)243211111221112221112555642221
Mean peak period (s)665555544455445554647555665454
Mean zero-crossing period (s)444433433343333443433444444343
Mean energy period (s)------------------------------
Mean wave power, kilowatts per metre------------------------------
Mean peak wave directionSEconcentration 80%ESEconcentration 99%ESEconcentration 99%SEconcentration 91%SSEconcentration 85%Sconcentration 84%Sconcentration 99%Sconcentration 96%SSEconcentration 92%ESEconcentration 94%SEconcentration 98%Sconcentration 97%SSEconcentration 91%SEconcentration 98%SEconcentration 98%SEconcentration 98%SEconcentration 99%SEconcentration 93%SSEconcentration 93%SEconcentration 94%SEconcentration 86%ESEconcentration 100%ESEconcentration 100%ESEconcentration 99%ESEconcentration 99%ESEconcentration 99%SEconcentration 98%ESEconcentration 90%SEconcentration 98%SEconcentration 94%
Mean directional spread (°)26.321.922.426.528.531.230.528.033.425.725.828.328.332.725.324.326.228.331.829.126.615.418.019.618.320.128.831.229.532.8
Mean water temperature(°C)8.78.88.99.08.98.88.78.88.88.88.78.78.78.88.98.99.09.19.39.59.69.69.79.810.010.010.110.210.210.3

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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