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Sandown Bay wave buoy daily means for Sep 2025

Daily means from the Sandown Bay wave buoy for Sep 2025, 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

1,436 wave-buoy observations covered all 30 days. Typical wave height was 1.9 ft (10th–90th percentile 0.8–3.5 ft), while mean average of more than one wave period type was 5.6 seconds (10th–90th percentile 3.6–7.7 seconds). Mean water temperature was 18.1°C (10th–90th percentile 16.8–19.3°C). 13 of 5,730 checked values (0.2%) were excluded by quality control. Across 15 comparable years, mean wave height was above the same-month mean of 1.4 ft and mean wave period was above the same-month mean of 5.3 seconds.

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

Typical Significant Wave Height

1.9ft
Mean: 2.1 ft
P10–P90: 0.8 — 3.5 ft
Recorded extremes

0.4 — 5.7 ft

Mean Observed Wave Period

5.6secs
P10–P90: 3.6 — 7.7secs
Recorded extremes

1.7 — 15.4secs

Available for 717 of 718 hourly samples

Observed Wave Direction

SSE

Circular concentration: 90%

Mean Water Temperature

18.1°C
P10–P90: 16.8 — 19.3°C
Recorded extremes

16.6 — 19.6°C

Compared With Previous Septembers

Historical baseline from 21,509 observations across 15 years.

Wave Height
2.1ft
0.7ft above mean
Historical mean 1.411ft
Wave Period
5.6s
0.3s above mean
Historical mean 5.3s
Water Temperature
18.1°C
In line with the historical mean
Historical mean 18.1°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 2025Last observation shown
Metric
Mean significant wave height (ft)334312211323334232121222222111
Mean maximum wave height (ft)457423422544446343232333333211
Mean peak period (s)556665564577658956665555554484
Mean zero-crossing period (s)444443443444444433334444443333
Mean energy period (s)------------------------------
Mean wave power, kilowatts per metre------------------------------
Mean peak wave directionSconcentration 99%Sconcentration 98%Sconcentration 99%Sconcentration 99%Sconcentration 99%SEconcentration 93%SEconcentration 92%Sconcentration 99%Sconcentration 93%SSEconcentration 95%Sconcentration 100%Sconcentration 100%Sconcentration 100%Sconcentration 98%Sconcentration 100%Sconcentration 99%Sconcentration 100%Sconcentration 99%Sconcentration 97%Sconcentration 99%SSEconcentration 79%ESEconcentration 99%SEconcentration 99%SEconcentration 99%ESEconcentration 98%SEconcentration 99%SSEconcentration 98%SSEconcentration 97%SSEconcentration 94%SEconcentration 94%
Mean directional spread (°)20.422.018.921.224.226.525.824.328.225.422.021.622.322.920.827.719.721.827.725.526.821.924.922.924.324.828.030.034.830.2
Mean water temperature(°C)19.519.419.219.119.119.219.319.219.219.018.818.618.318.117.917.717.617.717.817.917.817.717.417.217.116.916.816.816.816.8

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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