Mahé

Mahé is the largest and most populous island in the Seychelles archipelago, sitting at roughly 4°S on the Mascarene Plateau in the western Indian Ocean. At 27 km long and 8 km across at its widest, it holds the capital Victoria, the international airport, and roughly 90 percent of the country's 100,000 residents — yet its coastline is still a sequence of distinct bays and headlands separated by forested granite ridges that drop steeply to the shore. The tidal regime on Mahé is mixed predominantly diurnal. Unlike the reliable twice-daily cycle found on most European or American coasts, the Seychelles experience extended periods — particularly around the solstices — when one tidal oscillation dominates and the day produces only a single clear high and low. Spring range at Victoria Harbour (the reference station for the inner granitic islands) runs between 0.9 and 1.4 m above chart datum. Neap range drops to 0.3–0.5 m, and on some neap days the water level is almost static for six hours at a time. The consequence for planning: watch not just the tide times but the range forecast — a 0.4 m neap day behaves very differently from a 1.3 m spring day. The northwest and southeast coasts of Mahé operate under different monsoon regimes. The SE trade winds (May–October) make the northwest beaches — Beau Vallon, Glacis, Port Launay — the calm-water side of the island, with glassy morning conditions and organised swell arriving only from the north. During the NW monsoon (December–March) the pattern reverses: the northwest coast receives short-period chop from the Indian Ocean, while the southeast coast (Anse Intendance, Anse Soleil, Port Glaud in its lee) quietens. Between the two monsoons — April and November — there is a brief calm that locals call the inter-monsoon transition; winds are light and variable, sea state is minimal, and the water tends to be clearest. The Seychelles Meteorological Authority (SMA) operates the Victoria Harbour tide gauge, which is also part of the Indian Ocean Sea Level Observing System (SEALEVEL/GLOSS). Tide predictions from this gauge are published by the SMA and the Port Authority. The predictions on TideTurtle pages for Mahé come from Open-Meteo Marine, a gridded global ocean model, with typical accuracy of ±45 minutes on timing and ±0.2–0.3 m on height — adequate for beach and recreational planning, not for vessel navigation or precise mooring calculations.