About this site
About Mont Saint-Michel Tides
Edited by Orkhan Farmanli · Last reviewed: May 4, 2026
Mont Saint-Michel Tides publishes high and low water times, tidal coefficients, and the rare days the rock becomes a true island again. This page covers how the data is computed, where it comes from, and who maintains the site.
Methodology
Tide times and coefficients are sourced from SHOM (Service hydrographique et océanographique de la Marine), reference n° 2025-209, with Saint-Malo as the reference port for the bay. Each cycle is classified on the standard 20 to 120 coefficient scale: under 95 is a regular tide, and 95 and above is a spring tide. "Mont becomes an island" days follow the Office de Tourisme classification, which combines coefficient with local bay dynamics. We do not adjust SHOM predictions for atmospheric pressure or wind, and we recommend checking on-site signage before any crossing. The tide dataset is compiled to a static file at deploy time, so no per-request database query is involved.
Sources
SHOM publishes the official tide predictions for French ports. The Office de Tourisme Mont Saint-Michel Normandie classifies the days the Mont becomes an island. Both are linked from the structured data on every page.
Editor
The site is built and maintained by Orkhan Farmanli, an independent developer working on small focused web projects. The goal is a single page that answers one question well: when is the next spring tide?