The secrets of Quiberon Bay

Quiberon Bay is  an area of sheltered water protected by the Quiberon Peninsula to the west and by small islands called Houat and Hoëdic to the south.

These islands have a quite strong influence on the winds, known as site effect.

In summer, the thermal breezes are of great importance, they too are disturbed by the Peninsula and the islands.

The tidal streams between the islands, and the Gulf of Morbihan, which spills and fills through a narrow gap, make the water body quite complex.

The racing area should be on the NW part of the Bay, 1 NM off the ENVSN.



Below the wind statistics recorded in summer at Belle-Ile weather station (8 nautical miles away from the racing area).


The ENVSN is involved in this matter and provides some help to decipher winds and tidal streams:



Wind sensors placed at different locations in and around the Bay provide information on the wind observed in real time (every minute).

It is important to take into account the wind direction to determine which sensor is the most reliable. 

The "ENVSN" sensor, for example, is disturbed by the hills of the peninsula in the event of a westerly wind.



A webcam installed on the isthmus at Penthièvre faces the ocean to the west.

Open the feed in VLC: rtsp://


DECIPHERING THE BAY : In collaboration with the University of Lyon, ENVSN has developed a document dealing with thermal breezes, site effects and tidal streams in the Bay of Quiberon.

The document is in French only, with many pictures and graphs.

It is downloadable  HERE  for free.



The tidal stream atlas shown below refers to the tide at Port-Tudy on Groix Island. (max. 10 minutes difference to Quiberon)

During the Worlds neap tides are expected, so the tidal streams will be rather weak but not negligible.

Note: PM means "pleine mer" (i. e. High Water), BM means "basse mer" (i. e. Low Water)