Skip to content
Surfhog home
Menu

Royan wave buoy monthly means for 2021

Monthly means from the Royan wave buoy for 2021, including available wave height, period, direction, wind and sea temperature data.

Last observation shown

Data available:  to 

Latest

Period Summary

Programmatically generated summary. Hog Says

17,237 wave-buoy observations covered all 365 days. Typical wave height was 1 ft (10th–90th percentile 0.4–2.4 ft), while mean average of more than one wave period type was 8.5 seconds (10th–90th percentile 3.3–14.7 seconds). Typical calculated wave power was approximately 0.4 kW/m (10th–90th percentile 0.1–1.9 kW/m), derived from significant wave height and energy period. 548 of 34,474 checked values (1.6%) were excluded by quality control.

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

Typical Significant Wave Height

1ft
Mean: 1.2 ft
P10–P90: 0.4 — 2.4 ft
Recorded extremes

0.2 — 5.2 ft

Mean Observed Wave Period

8.5secs
P10–P90: 3.3 — 14.7secs
Recorded extremes

1.6 — 23.4secs

Available for 8,630 of 8,679 hourly samples

Typical Wave Power

Approximately 0.36kW/m
Mean: 0.72kW/m
P10–P90: 0.07 — 1.85kW/m
Recorded extremes

0.01 — 10.7kW/m

Calculated from significant wave height and energy period.

Available for 7,805 of 8,679 hourly samples with wave power

Typical Observed Wind

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

Available for 0 of 8,679 hourly samples

Mean Water Temperature

-°C
P10–P90: - — -°C

Available for 0 of 8,679 hourly samples

Chart showing grouped wave observations for Royan. Use the table on this page for a text version of the same measurements. To open daily observations, use a linked month 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; months run left to right.
Royan wave buoy monthly means 2021Last observation shown
Metric
Mean significant wave height (ft)221121111112
Mean maximum wave height (ft)232132221223
Mean peak period (s)9131187855910912
Mean average period (s)576555445666
Mean period Tm02 (s)455444444445
Mean peak wave direction------------
Mean directional spread (°)------------
Mean water temperature(°C)------------

Swipe sideways to see more months.

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.

› Wave Buoy List