Saint-Malo is just waking when I walk the city walls. Salty air fills my lungs. The sea below smashes against the ramparts. There is barely another soul on my hour-long circuit of the 2km ramparts, past a stretch of the Channel dotted with islands that for now are only reachable by boat.

When I return in the afternoon, everything is different. The outgoing tide reveals golden beaches and land bridges to islands that suddenly feel close. At Grand Bé, I follow the windswept path to the tomb of French writer Chateaubriand, the staccato shrieks of gulls in my ears. On Petit Bé, just beyond, the 17th-century fort crowns craggy rocks wreathed in blue periwinkles.

Talk in Saint-Malo isn’t about weather, but tides, which sweep across the causeways and beaches at a galloping pace – often rising up to 13 metres in a day. The shifts are so dramatic that locals use an app, Ask Malo, to track the tide in real time.

Shorts

Saint Malo and its ramparts at dawn (Photo: Mathieu Rivrin/Getty Images)