©Nohcab The Great Tides Show
Contemplate the high tide show is a must-see on the Opal Coast. The coastal horizon widens in a tonic atmosphere. To walk there safely, you need to be well informed, even more so during the equinox tides. It is also an opportunity for an educational approach to this phenomenon known since Antiquity.
Understanding the phenomenon of tides
Tides are a fascinating natural phenomenon for young and old! Seeing the sea retreat sometimes very far away is synonymous with a walk on the coast... where the sea was present shortly before. At Calais XXL, for example, it is the opportunity to walk at the foot of the cliffs of Cap Blanc Nez, between Sangatte and Escalles.
This magnificent natural spectacle has a scientific explanation that's not always easy to understand. Here are some tips to answer children's questions!
©Nohcab The phenomenon of tides has been observed since ancient times. The great breakthrough came in the 17th century thanks to Isaac Newton. This English scientist made discoveries about gravitation and the Earth's attraction. The movement of water is for him linked to the attraction exerted by the Sun and especially the Moon. When the Earth, Moon and Sun are roughly aligned, attractiveness increases and coefficients increase. This is especially the case during the 2 equinoxes, when the Sun is facing the equator and the length of the day equals the length of the night. In the Napoleonic period, the French scientist Pierre-Simon de Laplace established the method of calculating tide times.
Tips for walking safely during high tides
The essential tool: it's the tide table! This booklet is available free of charge at the Calais XXL Tourist Office or online. A tide cycle lasts about 12 hours. There are therefore about 6 hours between a low tide and a high tide: this leaves time to enjoy the immense space that the sea leaves us for walking. The important thing is to check the tide times carefully so as not to get caught out.
Today's tide table
XXL format tides
The strength of the tides depends on the coefficient. Each tide has its coefficient, indicated on the tide table. When the coefficients reach or exceed 100 for a few days, These are high tides! This phenomenon of high tides is even more spectacular during the equinox tides, in spring and autumn. This is where the vastness is revealed, inviting you to take a walk! But always with the necessary precautions.
©Nohcab 
©Nohcab The big tides 2025
When do spring tides occur? En February March et in September-October, when the Moon and the Sun are well aligned and close to the Earth (lunar perigee and terrestrial perihelion in winter). At these times, tidal coefficients often exceed 100, leading to maximum variations in sea level.
March 2025
- Saturday, March 29 – coefficients 104 / 109
- Sunday, March 30 – coefficient 112
- Monday, March 31 – coefficients 114/114
April 2025
- Tuesday, April 01 – coefficients 111 / 107
- Wednesday, April 02 – coefficient 102
- Sunday, April 27 – coefficients 101 / 105
- Monday, April 28 – coefficients 108/108
- Tuesday, April 29 – coefficient 107
- Wednesday, April 30 – coefficients 105 / 101
September 2025
- Monday, September 08 – coefficient 101
- Tuesday, September 09 – coefficient 104
- Wednesday, September 10 – coefficients 106/106
- Thursday, September 11 – coefficients 104 / 101
October 2025
- Tuesday, October 07 – coefficients 103 / 107
- Wednesday, October 08 – coefficient 109