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Royan wave buoy daily means for May 2025

Daily means from the Royan wave buoy for May 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

1,029 wave-buoy observations covered 25 of 31 days (81%). Typical wave height was 0.8 ft (10th–90th percentile 0.3–1.5 ft), while mean peak wave period was 9.3 seconds (10th–90th percentile 4–15.4 seconds). 58 of 2,058 checked values (2.8%) were excluded by quality control. Across 4 comparable years, mean wave height was below the same-month mean of 1.1 ft and mean wave period was above the same-month mean of 7.3 seconds.

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

Typical Significant Wave Height

0.8ft
Mean: 0.9 ft
P10–P90: 0.3 — 1.5 ft
Recorded extremes

0.3 — 2.6 ft

Mean Observed Wave Period

9.3secs
P10–P90: 4 — 15.4secs
Recorded extremes

1.8 — 25secs

Available for 510 of 518 hourly samples

Typical Observed Wind

-, -mph
Mean: - mph
P10–P90: - — - mph

Available for 0 of 518 hourly samples

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 518 hourly samples

Compared With Previous Mays

Historical baseline from 5,882 observations across 4 years.

Wave Height
0.9ft
0.2ft below mean
Historical mean 1.115ft
Wave Period
9.3s
2s above mean
Historical mean 7.3s
Water Temperature
–
Not enough comparable data

Chart showing grouped wave observations for Royan. 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 Royan wave buoy

Royan is part of CANDHIS, France's national in-situ sea-state observatory coordinated by Cerema and its regional partners. The station lies off the mouth of the Gironde, where Atlantic swell meets a wide, shallow and strongly tidal estuary beside the resort coastline of Royan.

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

Metrics are rows; days run left to right.
Royan wave buoy daily means May 2025Last observation shown
Metric
Mean significant wave height (ft)111-----0112111111111111-111111
Mean maximum wave height (ft)111-----1123211111122221-222112
Mean peak period (s)12-11-----11131066991313131067554-910910109
Mean average period (s)665-----4545554457444444-555555
Mean period Tm02 (s)454-----3444444445343443-444444
Mean peak wave direction-------------------------------
Mean directional spread (°)-------------------------------
Mean water temperature(°C)-------------------------------

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 Cerema CANDHIS coastal wave observatory.

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

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